The PI and NPI versions of these blowers are exactly the same other than the shape of the intake port. And either version of the blower will fit on either of the heads, as long as the intake gasket used matches the blower and you watch the water jackets (sometimes they don't match up 100% and need a dab of RTV to make sure they don't leak).
Assuming it actually does have all the brackets, $1500 is a pretty good deal for one of these blowers. You'll still need injectors, a MAF, and a fuel pump. Should be able to get all three of those for less than $500. A throttle body and decent cold air intake (JLT or
K&N) helps a good bit, too. On stock NPI heads, with stock PI cams, CAI, offroad Prochamber, it made a touch over 300 rwhp on the tires through the automatic transmission. That was with a 3.5" pulley running about 7 pounds of boost. A PI headed car would easily make 315, with a 5-speed making 325 or more. I ran 12.5-12.6 at 107-109 on the stock auto and rear gears. A 5-speed with gears, or an auto with a converter, should be able to push it well into the 12s. It definitely runs good for what it is, and is a ton of fun on the street.
Want it to go even faster? Get a water/meth kit to cool down the IATs and throw some timing at it. I pick up 7 mph at the track by just turning the water/meth on, which indicates nearly 75 more horsepower. Just the other day, I had the car retuned after porting the blower. It picked up 25 rwhp on the dyno from the porting, bringing it up to about 350 rwhp. And that's still through an auto. Throw in the extra 75 from the methanol (for some reason, it doesn't pick up power on the dyno when adding the methanol), and it's pushing every bit of 425 through the auto. Definitely ready to get back to the track to see how it runs. Hoping for mid-11s at 120+ mph!