1. he doesnt have a built motor
2. a stock t5 is fine yes do the swap
3. your engine isnt even gonna make 300 to the wheels
4. i know someone making 320 to the wheels on a MUSTANG dyno doing just fine cutting 1.6 60s and running high 11s with a 99+ v6 t5 if you want to try that route... i am not making any promisses though
your stall will be good out of the hole and consistant from a stopl, but so am i with a manual and slicks
its a mater of prefrence, are you a good enough driver to make up the et difference between the built stalled auto and a t5? do you want topend for highway or good ets, or both?