Edelbrock advertises their Performer 5.0 kit to make 300hp, Trick Flow (w/Street Heat intake) and Holley (Systemax II) advertise approximately 350hp, the FRPP kit is a kit thrown together by the vendor and FRPP does not advertise a kit hp for it.
My .02 cents is this:
Don't get hung up on the horsepower numbers, because there are a lot of accessories that go into making those numbers (bigger MAF, type of exhaust setup, etc, etc) that the number is not a guarantee. It is an ideal under perfect conditions with a perfectly matched setup.
That being said, I'd avoid the FRPP thrown-together kit and get either the Edelbrock or Trick Flow kit. The Edelbrock will be the most street-friendly with as-good-as-stock driveability and make respectable power. I think it's a great kit for a car that stays on the street 95% of the time and only goes to the track a couple times a year.
The Trick Flow kit will produce more peak power than the Edelbrock, and both the Twisted Wedge heads and Track Heat cam will make more power than the Edelbrock counterparts. The Trick Flow kit is also VERY complete, since they provide rocker arms, pushrods, and other miscellaneous items the others don't come with.
The Holley kit is ok, it makes good power. The intake is very popular (huge ports, high rpm), but I've heard various complaints about the Systemax heads (sub-par valve guides) and most people aren't thrilled with the Lunati cam grind they include. However, from my understanding the Holley heads are good castings (I can't remember if it's Brodix or Canfield that casts the heads for Holley, one of the two I think).
Hopefully others will chime in.
