I started this in a new thread to avoid highjacking a paid vendor thread.
From what I see the upper limit to weight shaving from Giulia 2.0T is around 150lbs without seriously cutting into functionality and getting to that goal involves a lot of money, parts that currently don't exist, and some changes in functionality. Everything is a tradeoff...
(most weights and prices estimated)
CF wheels save 56 pounds at a cost of $12,000 ($214/lb)
Lightweight rotors save 16 pounds at a cost of $1500 ($93/lb-numbers from similar BMW parts)
Titanium lug set saves 2 pounds at a cost of $350 ($175/lb)
OEM CF hood saves 6.4 pounds at a cost of $6000+ ($940/lb; way too much--this would be much less $$ if it were an order able option)
Disable start-stop and install a lighter battery saves 15 pounds at a cost of $200 ($13/lb)
Aluminum battery cables saves 5lbs at a cost of $200 ($40/lb, assumes stock cables are copper and ignores installation labor cost)
Titanium suspension bolts saves 20 lbs at a cost of $2000 ($100/lb, totally made up numbers, some of this is unsprung)
Titanium springs save 20 lbs at a cost of $4000 ($200/lb, totally made up numbers)
Light weight exhaust save 11lbs at a cost of $1600 ($145/lb, 2.5 inch straight through--this is loud)
Light weight speakers save 5lbs at a cost of $400 ($80/lb, assumes Neo-magnet speakers are available in the right size)
Sparco seats save ?? lbs at a cost of $5600, only available in black, no seat heaters and reduced power controls
P-zero Corsa tires save about 20-30 lbs of unsprung rotational mass, but are very expensive because the tires don't last very long and are not usable in a lot of conditions that many people expect to use their car.
Lightweight forged wheels save about 30 pounds but the cost is still around $200/lb. Forged wheels might be more capable of handling road hazards than CF wheels, I do not know.
Lightweight cast wheels save about 30 pounds at a cost of $800-$1200 which looks a lot better than the CF or forged wheels $/lb, but it is not clear to me if that a cast wheel that weighs the same as a forged wheel is really strong enough. After all, wouldn't this put the forged wheel mfgs out of business if the cast wheels are good enough?
I did not include lightweight flywheel or torque converter as I suspect that most folks (including myself) will not like the rougher idle, increased stress on the transmission, or the need to pull the engine to install it.
Shaving weight is certainly expensive and I agree that the best weight to shave is from the wheels. Weight shaved from wheels improves handling and yields a disproportionate improvement in acceleration. However, for Giulia 2.0T shaving 250 lbs is equivalent to adding about 20HP to the engine while also improving stop-and-go fuel efficiency. It is only possible to improve engine performance so much before major drive line changes are needed and/or the vehicle is no longer street legal (won't smog).Speaking from personal experience modding cars, including full exhaust systems, there's a point where cost per amount of weight saved doesn't return enough value to worry about. If the stock system only weighs approximately 38 lbs, there isn't enough potential weight that can be saved, to be worth the concern. Even if you could cut that in half and save 19 lbs, that's not enough to even feel the difference in the performance of the car. The cost of titanium pipes in my opinion, wouldn't be worth it in this particular case.
I've learned that when it comes to saving weight on a car, not all weight is equal in what it can do for performance. The type of weight you remove, and where you remove it has more of an impact than anything else. You can easily spend thousands on carbon fiber body parts, and maybe save 40-50 lbs, which will make essentially no difference in performance that you can feel. As far as quarter-mile performance, you have to remove 250 lbs of static weight from a car just to gain 1/2 a second at the end of a quarter mile. It's not easy to remove that much weight without gutting the car, and it's not cheap. Not worth it in my opinion; I couldn't tell the difference in 1/2 second anyways.
The best kind of weight to remove, is unsprung rotating weight. That's found in the wheels, brakes, engine flywheel, clutch and driveshaft. Saving 19 lbs in the exhaust system you wouldn't even be able to tell. Saving 19 lbs in unsprung rotating weight you would notice immediately; it makes that much of a difference. Unless you're going for an all-out race build where every pound matters, for a street build, it makes better financial sense to spend your mod money wisely on those areas where you can actually feel the result.
Alfa already gave us a carbon fiber driveshaft, so that's done. Lighter wheels will make a huge difference in performance. Lighter brake rotors just add to that difference. Flywheel and clutch are a different matter, and while they do make a difference, there's more work involved in changing them out, and it can make the stop-and-go performance not as smooth as stock. Where a lighter flywheel and clutch make a difference, is once you're rolling. The throttle response and engine braking are noticeably improved, which you really appreciate in the corners and out on a road course or autocross. Around town... it's more touchy to get the car going, but for those who are more hardcore and want that kind of snap-quick response, there's nothing like it.
For this particular car, my first area of improvement would be lighter wheels. I think that would give you the biggest bang for your buck as far as something where you can feel a difference. Of course you can do chip mods and such, but those void your warranty. Keeping in mind Alfa's past reputation, I'm not in favor of voiding my warranty.
So Joe... as for this cat-back system, I'm curious... why did you choose a 3 inch pipe? Did you try a 2.5 inch pipe system? Was there a performance advantage, or did it just sound better?
From what I see the upper limit to weight shaving from Giulia 2.0T is around 150lbs without seriously cutting into functionality and getting to that goal involves a lot of money, parts that currently don't exist, and some changes in functionality. Everything is a tradeoff...
(most weights and prices estimated)
CF wheels save 56 pounds at a cost of $12,000 ($214/lb)
Lightweight rotors save 16 pounds at a cost of $1500 ($93/lb-numbers from similar BMW parts)
Titanium lug set saves 2 pounds at a cost of $350 ($175/lb)
OEM CF hood saves 6.4 pounds at a cost of $6000+ ($940/lb; way too much--this would be much less $$ if it were an order able option)
Disable start-stop and install a lighter battery saves 15 pounds at a cost of $200 ($13/lb)
Aluminum battery cables saves 5lbs at a cost of $200 ($40/lb, assumes stock cables are copper and ignores installation labor cost)
Titanium suspension bolts saves 20 lbs at a cost of $2000 ($100/lb, totally made up numbers, some of this is unsprung)
Titanium springs save 20 lbs at a cost of $4000 ($200/lb, totally made up numbers)
Light weight exhaust save 11lbs at a cost of $1600 ($145/lb, 2.5 inch straight through--this is loud)
Light weight speakers save 5lbs at a cost of $400 ($80/lb, assumes Neo-magnet speakers are available in the right size)
Sparco seats save ?? lbs at a cost of $5600, only available in black, no seat heaters and reduced power controls
P-zero Corsa tires save about 20-30 lbs of unsprung rotational mass, but are very expensive because the tires don't last very long and are not usable in a lot of conditions that many people expect to use their car.
Lightweight forged wheels save about 30 pounds but the cost is still around $200/lb. Forged wheels might be more capable of handling road hazards than CF wheels, I do not know.
Lightweight cast wheels save about 30 pounds at a cost of $800-$1200 which looks a lot better than the CF or forged wheels $/lb, but it is not clear to me if that a cast wheel that weighs the same as a forged wheel is really strong enough. After all, wouldn't this put the forged wheel mfgs out of business if the cast wheels are good enough?
I did not include lightweight flywheel or torque converter as I suspect that most folks (including myself) will not like the rougher idle, increased stress on the transmission, or the need to pull the engine to install it.