Concentrate on the GTO. Let the customer cars do the talking for BPA. "Shop Cars" can be nice, but finding time to work on them, and keeping enough work rolling through the doors to pay for them are a bitch. Which goes back to time to work on them. If you've got time to build and drive bitchin Track Car and your a small shop there ain't much work coming through the door.
Driving is a whole different animal. Stepping into a low 10- even mid-9's car is a whole lot different than beating around in a 11-12 second car. It'll come with experience, and practice but it won't be easy.
Edit additional thought:
If it's fast and well built no matter what it is ill bring attention. Look how many Camaros, Mustangs etc. are out there. Commonality shouldn't be a concern.