[hayden55]

Mustang mod wise if you can think it, you can do it. I can put in a 5 speed, 6 speed, gear ratios from 2.73-4.56 FD, underdrive pullies, electric water pumps, I can even swap the hydraulic steering on any 05-14 mustang to EPAS from a junkyard 11-14 car but cost is around 1000$ and weight gain is like 40 pounds. Not really worth it since i'm into autocrossing and will eventually compete in a 300hp 4.6 vs 500+ 5.0's.
The only thing kind of ironic though is that if you have a v6, compatibility with half the mods I listed is kind of nulled out. lol
In it's current state it has the cats deleted, louder mufflers, tune, intake, charge motion control valves deleted (cmcv deletes: mistake, cold starts use more gas, less low end, no noticeable change in top end). Making 350bhp. Then full suspension: custom spec coilovers by me (Ground control, bilstein), adjustable: swaybars, endlinks, watts link) and 285/35/19's. And weight reduction here and there to take the car from 3600 to 3480. But i'd rather not "race turd" a $20,000 automatic muscle car and instead start with a 05-06 $6000 manual car, starting at 3450 pounds with the lighter pre gt500 frame.
I want to compete in a stock modified class with the car so my mods will have to be legal so: I will swap the trans from the tr-3650 with 5th from 0.68 to 0.62, then weight reduction from 3450 to 3200 base weight for the class. Build a small trailer to carry tools for the track and 315/30/18 wheel setup.

I wonder how he found his values for Cd and ft2 for the mustang. I'll have to go to his thread and read it after work!