Lowering springs will not turn off the dampers. If you go too low, you can damage them and cause them to leak.

What are you calling your "secondary cat"? There are a lot of threads on here with various aftermarket exhausts and a lot of people replace the catted downpipe with a straight pipe. This is illegal for the street and you would need to address the check engine light that this would create.

 

Yeah I understand that part which I’ll probably end up doing. Do you know if there’s any way of turning the dampers off or not damage them

 

Your terms are confusing. Dampers dampen the bounce inherent in the springs. You can't turn them off as they are mechanical and will compress every time the springs compress. If you use much shorter springs, you run the risk of the dampers being too compressed for their design creating excess pressure on their seals which can cause leaks and ultimately failure.

 

First question I have is "why"? Why do you want to do these things? Are you trying to set up your QV for track? What you're calling "dampers" are also known as shock absorbers, and you don't want to turn them off (which isn't possible anyways). Are you just wanting to lower your car? If so, be aware that you're going to have clearance issues on the street, including the possibility of damaging the expensive extending front air dam.

As far as removing exhaust components, are you doing it to increase power, or just for sound? As @maddmike said, there are a lot of threads of people modifying the exhaust system of a QV, but removing a cat will render your car illegal to operate on the street, and there's a pretty hefty fine if caught.

It would help us to know what your intended purpose is for modifying your car.