Well you should go and do a search and look at all the stuff that has already been discussed about the kit there is some good info and opinions there, I have a lot of topics on this kit in Windsor Power.
I love my kit and think it was worth every penny, it makes great power from 3500 up. I shift at 6200 and it is still pulling. Now the cam I feel like others can be much, much better. I was running the Non-Emission cams but I have my motor apart right now to swap the cam to a Anderson N-61 which will really wake the motor up. I did get the newer style heads PT#300-575 last spring by accident they are being release this spring per Holley. These heads do not have the .40" rasied exhaust ports and they are assembled by AFR for Holley. I have the 2.02" x 1.60" stud mount, and they fit with stock pistons and the .509 lift Holley cam. I had .139" PTV clearance. I was having oil consumption problems so I tore the motor down to find broken valve seals and bad valve guides after 3000 miles, the heads are being replaced no questions asked by Holley. I hope to be deep in the 11's with my new combo in the spring after I get it back together, hopefully by the first half of April. I am running the 24# injectors instead of the 30# because I have heard that to run the 30# you have to have the pressure to low and they don't have a good spray pattern so I went with the 24's. I wish I would have went with the 70mm TB though.
As far as streetability, it is fine doesn't over heat ( I have a 195 thermo, Ron Davis radiator, Stewart H2O pump) and the car never runs over 180 degrees. The idle is mean and I can't get it to idle below 1100 or it loads up due to all the overlap the cam has.
I think if you go with the kit you can not beat the Holley intake, you will never out grow it. I know the heads I have flow damn good numbers for box stock and are close to the AFR's but I have 62.1cc chambers, the AFR's have 58cc which will give you a little more compression. I think either head would be a good choice. Most of my mods are in my sig, if you need any more info either post it here or e-mail me at Rick91GT@onemain.com.
Good Luck!
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My Ride Check Out My Site 91GT, Holley SysteMAX II Kit-Heads 2.02" x 1.60",Full MAC exhaust 1-5/8" Long tubes, 2-1/2" O.R H-Pipe, 2 1/2" cat back, 12" K&N Filter, RNH PERFORMANCE Ram Air, Ron Davis Radiator, Full Suspension,3:73's, Welds, Best on new motor-12.60 @ 108, no traction 1.98