By my understanding of the definition of Pro Street... The car has to have big tires. Like 30-33" tall, 14-20"+ wide. It needs coil over shocks, and a 3 or 4 link rear suspension. You should have a cage installed, at least 10pt, and the front end should run the thinner tires. The rest is up to you. If you cant do the fabrication, it will cost a lot of $$ to have done. Back-halfing runs from $5K-up, plus materials (materials including narrowed rear, wheels, brakes, shocks, springs, lines, tubs, rod ends and steel parts). Also factor in doing it twice. Once to fab it, then then again after it's all painted/coated. Also keep in mind, it has to be stable and safe too. The welds cant be snotty, or half done, things like fuel system and batteries need to be mounted, tubs sealed, 1/4s stretched..it's not a "buy th $500 Comp Engineering kit and drop it in" deal. Good rod ends are very expensive, and if the car is to be street driven, you cant run cheap ones for very long before they get destroyed. Also, braking system and suspension setup are critical. If it was easy, everyone would have it..lol. Properly done, a real prostreet can run as well as it looks, and be safe too.