can give you a custom tune (usually around $300, give or take)? Once you start adding mods, the off the shelf chips can be off in air fuel ratio and optimal timing mapping and a correct tune can add power and responsiveness throughout the powerband. Butt dyno opinion re: 1.driveshaft...uh uh. 2. pulleys....~10HP 3. upgraded intercoolers....probably no noticeable gain unless you turn the wick up (varying opinions on what is suggested as maximum boost ranges from 17-20 psi), then there would be some butt dyno gain (educated guess 10-15 HP at maximum boost). Good luck in your decision, Mark