"Occasionally" is something you do with a stock car. There is nothing that you'll ever do to that car to make it non-driftable. Fix the car and make general improvements. Don't even worry about the driftability.

The clean SR engines will never come down in price. What people are paying now is what I paid 3-4 years ago. Demand is still high, and the supply is getting low. I've heard Taka say that there are no more S13 Silvia on his island in Japan. They've all been cut in half and shipped here. $2500 would be a great deal on a good looking stock S13 clip. Expect to pay more.

Throw the KA-T idea right out the window. Someone who can't pay for or install a stock SR isn't going to take the time to do a KA-T well enough for it to last more than 10 days.

Please for the love of God learn how to use punctuation and capitalization.