ditchsnake, now that the big Heartbreaker Maggie came out, you should be able to secure a great deal on the older Heartbeats (2300), and the Magnuson tune should be good for the power level you want. That said, however, I would still get a custom tune dialed in for you car, especially if you have the A8 trans.
My car is just about perfect for the street, makes 560 rwhp here in NJ, drivability is excellent with Ted Jannetty's tune and even wifey can drive it (in snow/ice mode, haha). There are several reputable tuners even here on the forums, I'm sure you can find one who will remote tune your car.
I know a good tune ain't cheap, but that's not where you want to skimp, peace of mind is king IMO, especially when you can save thousands on the blower itself. I recall someone selling a kit a few weeks ago here, definitely worth a search.
Good luck
