that`s what is still missing on Top Gear

"budget track car"

 

MX-5, as BigE posted - Best low budget track car out there. If done right, very quick on a twisty circuit. I see you already have a STI, those cars are pretty good out of the box despite the AWD.

 

Miatas are great for the track too. Another car worth considering might be a Porsche Boxster.

 

I have driven a few cars on the track here at BIC and honestly nothing NOTHING beats a Caterham!!!
Caterham Cars - Designed for racing, built for living
It is relatively inexpensive to buy and cheap as hell to run… which is very important if you plan on hitting the track frequently
Performance of the Caterham is amazing I have seen is lap at RGT and both cars we driven by remarkable drivers.
I think the “Academy” is more than enough but it you like go for the “Superlight R400” anything more is just too much!!!

 

Solstice. Those are clowning folks on the SCCA circuits, even the Evos and Subies.

 

+1 on the Porsche Boxster

 

Are there any kart tracks near you? Do some searches and see what leagues and types of karts are raced in your area. You can usually pick up a good used 80 or 125cc shifter cart with all the extras for 5-8K here in the states. IMO it's the best learning tool. The cost per hour of seat time is very very hard to beat & you'll get wheel to wheel racing. It usually costs about 3K per season in fuel & tyres.

 

they're both awd.. unless you do a rwd conversion but i dont know how cheap those are

 

I would say an E30/E36/E46 M3 or even a C5 Corvette.

 

oh...damn,forgot about the RWD requirement

thanks