try starting it from hot a good few times,check the carpets if there wet,open the sunroof and check for rot,listen for typical tapping cvh engine,any smoke on startup or on boost,warped disc's also common,keep it running a little and keep an eye on the temp also the fans should kick in,also hpi check or sighns of damage,unless your paying £4k imo a average £2k you should expect it to have had a bit of welding and a splash of paint but should be a tidy useable car,the other way I look at things is a second hand decent engine can be had for arond £400 but rot is a bigger problem they drive like shit,you will always be swearing at it but when it works and comes on boost then its worth it