the 7.5 rear will be fine for now. mine has been beaten every day with no signs of giving up. my 4R70W however is ready to give up the ghost
get a shift kit if you plan to go with the Auto and 3.73`s are plenty with the procharger. any steeper gears and you will need soft rear springs and sticky tires to get traction. i`m having a hard time planting my tires now with my 3.73`s and 99 gt vert springs
what year v6 are you planning to buy/ the single port (94-98) are different than the split port 99+ kits for the procharger
i am running an 11 psi kit on my 98 singleport with stock injectors and the supplied FMU and harland sharp 1.8 rockers. i`m making around 260 rwhp and the 7.5 rear is holding up just fine after 40,000 miles since i supercharged.
i have 42lb injectors and a Pro-M univer MAF meter to go in and an RPM 215/230 .494"/.524" cam.
i also need to get a chip burned for my combo when i install these mods.
the 11psi procharger 94-98 kit works fine with the stock setup
the 11psi 99+procharger kit requires a chip and 42lb/hr injectors in addition to the 255l/hr pump supplied with the kit
the 7.5 isn`t as weak as most people claim and it can be strengthened to the same as the 8.8 with the addition of a TA performance rear end girdle. the stock 7.5 is not as strong as the 8.8 but the stock 8.8 is no winner either. it would however be better than the 7.5 if hp levels exceed 300 rwhp.
check out
www.v6power.net the guys on there have alot of experience with high hp levels on the 3.8 stang. also justin at velocity mustang can burn a custom chip for you he frequents that board as do alot of other guys that make 3.8 performance parts. look up a guy named RGR if you want a custom cam he`s really good.
i hope this helps and i`ll try to answer any other questions you may have