DIO MIO!!! that is some itinerary!...your gonna need a vacation from your vacation
Milano, I think that Hotel is very close to the Duomo, walking distance. If you are able to have a lunch or dinner before you leave for Liguria (Levante) try Da Giacomo Via Pasquale Sottocorno 6 OR Boeucc (Old School Classic Cucina Milanese) Piazza Belgioso 2.
The Alfa Romeo Museum is on the outskirts of Milano in Arese.
Next Stop Liguria! Your staying in Levante which is outside the cinque terre. The "5" Towns are accessible via boat or train. Take the train, cheaper & faster. My favorite town in the Cinque Terre is Vernazza. Not sure you can do all 5 towns in the time your there. But in Vernazza; Belforte is a long established place....nice local cuisine...a bit touristy now...but still a good meal.
On to Florence & Chianti!!....When in Florence and when you are in the second place which is in Chianti, you have to have Pappardelle Ragu di Cinghiale. (Wild Boar Ragu with a wide ribbon pasta). Take in the sights! Lots to see & do, near the Piazza della Signoria is the Academia; Obica Mozzarella Bar
Find a bottle of Chianti Classico Gran Selezione & have fun!
Roma, the Eternal City is just that!!! Step back in Time. Not enough time, choose your sites wisely. IF you like seafood, there is a restaurant near the Pantheon called Trattoria La Rosetta Via Rosina 8 all seafood. otherwise Trattoria Dei Mori Via San Nicola 20...solid place. IF you had more time I'd send you to the rooftop restaurant at the Sofitel Villa Borghese OR La Canonica in Trastevere.
Amalfi Coast Positano all I can say is that your Hotel is highly regarded! I have never eaten in Positano. when I am on the Amalfi Coast I always stay in Sorrento and do day trips. BUT if you go to Capri, have lunch at the Villa Verde.
If you have any questions just let me know. I'm happy to help in any way.
As far as your car quest, you are headed in the wrong direction...you need to go to Emilia-Romagna to see the BIG THREE: Ferrari, Lamborghini & Pagani