No one else has mentioned it so I will...97 GTPs are the red-headed step child of Grand Prixs. LOL I say that with affection as I have a 97. The reasons they are that way are because they have a one-year only PCM that sometimes has issues with false KR, they have the coolant overflow bottle behind the driver's side headlight (later years moved it to the passenger side shock tower...you'll want to switch to this style overflow when you do your intake), they have a one-year only alternator setup, they have a different vacuum line routing, they have a one-year only supercharger design because of the vacuum setup. They have a different style of traction control system...which is to say it's almost non-existant. You have vacuum reserviours (or however you spell it) in each fender that look like overgrown grapefruit. The DIC is different...I could go on but you're getting the idea. Whenever you are looking for parts, be sure you are talking about a 97.
Good news is that a lot of this stuff can be changed. You can use a 98+ blower if you change out the vacuum lines to 98+ lines too...and that's not hard or expensive. The Alternator can be changed out along with the bracket for it if you want to but it's not necessary. The coolant bottle can be moved. If you want you can change out your PCM to a '98 but that is pretty involved with either replacing your entire wiring harness with a '98 or rewiring the harnesses that you have now to the '98 schematic.
Lastly, what do you mean by Street Legal? The California Smog NAZIs (misspelled CARB) will only allow certain things. The K&N intake is CARB legal as are the TOG headers for 97. However, everything else is not. The 180 t-stat, rockers, ported SC, intercooler, and pulley would all be considered illegal and not for street use in CA. Of those, only the intercooler would really give problems at a smog test as our cars will pass the sniffer with just about anything done to them. We had a 536 WHP GP pass the sniffer test...my car passes the sniffer test...it's the visual that will get you. Intercoolers change the look of the engine bay enough that a sharp eye'd smog tech may catch it and fail you. Gotta love CARB.
So what part of CA are you in? We have a club down here in SoCal that is pretty helpful with this stuff though it's not as active as it use to be.
