Thanks everybody, I guess the Toyota route is probably the way to go, at least to get a basis for further experiment. Has anybody who's had a Toyota set-up used their car on a circuit? Was it any good? Did excessive udersteer rear its ugly head? Done two trackdays recently, current set-up works pretty well, turns in on command, understeer really only noticeable when turning in too fast on a trailing throttle. There's a good, if expensive, (£195) trackday at Bedford Autodrome on 25th Jan if anyone's interested.
See http://www.clubautodrome.com for details. Price includes a short outing in an F2000 single-seater, a great experience.
Cheers,
Back to work.