03GT5spd

ok so i have a 03 gt 5spd when i bought the car it already had a stage 2 clutch and a short thro i think it might have gears but im not certain compaired to my dads 89 5.0 it feels like it but i knoe they came with gears compared to the 5.0 i have put trick flow underdrive pulleys on it and have been happy with it so far but last time i raced my brother inlaws ws6 trans am at about 90-100 he creeped past me since then i got a diablo predator tuner but havent raced him yet so i just ordered yesterday trick flow 75mm throttle body trick flow elbow plenum also 75mm and a cold air intake k&N so my question is how much power will i gain from the new mods plus the tuner and will he still creep past me at higher speeds if so is that cause he is a lighter car and more power and taller gears ?

suoperdave84

You might get better responses posting this in the right section. This section is for the 2005-2009 Mustang