I'm looking to buy some relatively hard to find cars in a low price range.?

Good luck. I hope you know hot to fix cars. Most of those cars require high maitence and the cost of parts are huge. I say you need about 15k to even get started. If you want something in great condition about 25k. I own 3 of the cars you have listed. M3,VR4 3000gt, WRX. I due all the work myself. Wait until you have to replace a trany or turbo. Will be over 5k if you can't due the work yourself lol. You can purchase a talon. They are turboed and go for cheap. Increase the size of the turbo and install an intercooler will run you about 1500. You can find other fun cars. Try Creigslist. I have found some good deals on there. Look in states were people don't have many of these cars.