I recommend being very careful about making major design changes to the vehicle. The more you mess with these cars the worse they become in terms of reliability and resale value. Very few shops have the ability to modify a car and maintain factory integrity. Most of the aftermarket stuff is designed to lower than OEM standards so the more aftermarket parts that you put on a car the more the reliability and reparability is reduced.

If it was my car I'd start with a tire size and stance that you like and then work from there. You'll most likely need an 18 inch wheel in order to find high performance tires. 18 inch wheels will give you enough room for 14 inch brakes which is what you'll need with that much power. You should be able to fit an 8 inch tire on the without any mods, if you want to go bigger than that then you need to start looking at making modifications. An 8 inch tire isn't going to handle the power that you are putting in the car so you'll need to figure out what you want to do. Once you start modifying the body and suspension for larger tires you get on a slippery slope and who knows where you end up.

The short answer is that what you want can't be done very well, especially on a budget. If you want to go down this path then set a budget limit and figure out what you can do within that budget. Trying to turn an E body into a Porsche or a C8 or even a Hellcat isn't cost effective. We learned this years ago with Tim's Valiant. By the time he was done it cost 2x of what a used Z06 would've cost and a Z06 would've been the better car. You'll run into the same problem with your car. You can spend $100K on it and a nice 911 Turbo will still out perform it on the street, road course and drag strip and have better resale value.