westfield and tiger are two top ones off the top of my head. pluss i think you can buy caterham 7's in kit form but cost a fair chunk.

do NOT (if they are still trading) buy a robin hood kit. we got a robin hood 2b kit as an impulse buy off my dad's mate. he'd got it to build for a customer and hadn't taken a deposit and they then pulled out so we got it on impulse. the WORST kit car you will ever come accross! we got rid in the end and took a loss of £1500!!!!

some tigers are designed to take twin bike engines too so are stupidly fast!

all about what you want the car for. can fit most engines upto small block v8's!