Turmoil Pro ($189):
http://www.amainhobbies.com/product_...oducts_id/6952

Hyper 7 TQ Sport ($239)
http://www3.towerhobbies.com/cgi-bin...?&I=LXJLE8&P=7

MBX5 ($319):
http://www.amainhobbies.com/product_...oducts_id/1817

Matrix Pro ($349)
http://www.amainhobbies.com/product_...oducts_id/9827

These are some kits that are popular that also leave you enough money (about $100 - $300) to drop an engine into them. The Matrix Pro has lots of CF and nice features, but will obviously require wheels and tires which will be between about $20 (Supra Sales on Ebay) to $60, so it might be a little out of your stated budget. The MBX5 Im pretty sure is the "standard" version, not the "R" version, so you may find it lacks some of the features the others offer for the same money (not sure, just pointing it out). The Turmoil Pro is obviously a steal for that $189, which is why I bought it, heh. The Hyper 7 seems kindof like that old favorite that never goes away. Based on what people say around the boards, I put it about with the Turmoil in racing ability (good enough that most people wont notice the difference, but not necessarily at the top end of its class in todays lineup).

Based solely on what you get right from the start, Id say the Turmoil is probably about the best in that lineup. Even then, for the cost difference between it and the Matrix, you could probably get all the CF upgrades for the turmoil you'd want, and fix anything else you might not like about it. Plus, the stock tires are the best factory-included tires that Ive seen (not that there arent any better, but just pointing out that you would probably be able to race on the factory tires without being disappointed).

One thing is that I hear that the Xray and Thunder Tiger EB4 S3 are more popular over in the UK, so that might interest you. In fact, you might make sure that whatever you get is equally well-supported in the UK so you dont have to wait a month for parts to ship overseas everytime you need them.