Dunno about a smaller blower pulley, esp on a M122. It's probably sitting at aprx 485 rwhp as is. What it needs 1st is a much bigger HE, and the IC pump from the 13/14 GT-500. If you want more power, LT's might be the ticket, plus the twin 65 /67 mm TB + 93 tune....albeit not cheap.
I def don't want to go the smaller pulley route. The newer '13/'14 2.3 TVS is a direct bolt on and typically nets numbers north of 600-625 to the rear wheels.
As far as the HE and IC go, I will be upgrading them. I am waiting to see what DOB is going to release and saving in the meantime! IF I find a used or take off HE I'll grab it while I wait. May end up with one of the big Afco or C&R HE's don't know about the fans or not but since I am in Houston Cooler IAT's for more consistent power will be a priority.
Not too concerned about LT's for the price and hassle if install you don't get much in return, heck the TVS swap is about the same price and nets 100+ hp more.
At least you don't have to mess with forging the eng, and a ton of other mods. The tranny is already rated for 600 ft lbs tq.
Heck it even comes with heat extractor hood vents.
This is the biggest reason I went with a GT500 over a pre owned S550 or a Boss. They were all in the same price range but I knew I wouldn't be happy with the stock power numbers. The GT500 is set up to run up to 750 or so RWHP without any major work or issues. I don't know if I want to go that high but its nice knowing I can considerably easier than my other options.
It's a superb starting point. Perhaps an eaton tru-trac and maybe a BMR watts link, bob's auto sports rear axle catch can, eng catch can. Are you going to lower it ? Then toss in the new LCA's, adj UCA, and lca relocate brackets.
I love the way it rides currently its stiff enough that it feels very planted compared to my '09 GT, but its forgiving enough that my wife and son don't complain. That being said I may lower it an inch or so, however I am really liking not having to maneuver funky to get in and out of driveways and such (I did just come from a truck too so I miss the curb hopping ability and all!)
Did it come with the 285 rear / 255 front setup? The ones I looked at had 18" x 9.5" wide rims at all four corner's. IMO, I'd go with a bigger front tire, like a 275 or 285. With 285's on all 4 x corner's, then u could rotate front to back.
Yes 285's in the rear and I think 255's up front is still standard but they are 19 X 9.5's on the 2010. I will be looking at doing a square set up for sure. another posibility is to get the 10" wide versions from American Muscle and get something in the 300's since traction will become an issue.
I looked at a 2008 GT-500 just a few days ago, down at the body shop, and those front 255-45-18 tires look a bit too much stretched on the oem 9.5" rims.