[INDYTRAKPAK]

Curious. I have a 435 HP Roushcharged Mustang. Would like to get it up to 500ish. I think I read the 2008's have the newer smaller (or better) pullies insatlled unlike the 07 and before- so I'm thinkin' more air flowish type stuff? I have a Roush Trak Pak and know it has the off road exhaust whih is killer- but can it be improved to get me to 500hp? and - don't wanna lose my warranty- no problem buying ROUSH parts. Thanks

[BLK_ROUSH]

Advice on upping the HP on the 05-09 ROUSHCharged mustangs .....

Just about any mod to gain HP will void your warranty, even RPP parts.

With a 2.57 pulley, CAI and some tuning expect 420- 450 rwhp 390-410rwtq. But note, the CAI will void the warranty. At least, that's what I understand to date.
I'd confirm with ROUSH if you're that concerned with a warranty.