If your going with TD-05's you can still get over 550rwhp on them them. See Fred's Z in ride section.Dyno'ed with 555 and has every part on his car that you could dream of and got this: DYNO TESTED-539.4 RWHP at 481.0 lbs on 17psi. Mostly because his motor is built. But if you go with 740's you'll need the AFC/AFR to fuel tune. Don't be fooled ,Stg XII Z's don't dyno over 550rwhp ( 9 out of 10 don't ). You need motor rebuilt etc,etc. But if you think big, no short cut's, :)