I concur, they are not worth $500.00, however if you shop around as I did, you'll pay alot less than $500. Why do you need AccuFab, Diablo, and Steeda to inform you you if something that you wanna buy is worth installing on your car?
Listen, Accufab's full of BS and I'll tell you why. 8.5hp is objective to the customer making the purchase, whether that's $300, $400, or $500 is in the eye of the beholder. Sencond point on AccuFab, I used to own a 01 Lightning prior to my GT and AccuFab has the biggest selling Throttle Body with the published gains being <b>8HP</b>. IMO, thier all going to be on the band wagon, it's just those vendors havn't released theirs yet so of course you should "Hold Off".
Having said all that, if 8.5 HP on a stock GT seems attractive to you then shop around, I did. I got LFP's 62mms version for alot less than $500, took me 10 minutes to install, throttle responce is GREATLY Improved, it pulls much harder and I'm sure it equals HP and TQ somewhere but I havn't put it on a dyno yet.
I'll be heading to Strictly Performance as soon as I can. But also remeber, a dyno isn't the end all and do all. Sometimes it shows up at the track and is dead on the dyno, speaking from personal experience from my 01 Lightning having many dyno pulls. Case in point, I put a Torque converter on my Lightning and picked up 2/10's at the track, but it didn't show up on the dyno.