help me choose a new car.

[Bruce750]

Hi, I'm new here. Just after some advice please. I'm about to start a new project for a track day car for next year. I've decided on either a E30 325i Sport, or a 535i Sport. Either way I want to drop in a S36/S38 (3.6/3.8) M5 straight six. I'm not after good lap times, I'm after some fun, and somthing different from the Caterham 7, Impreza & 911 Bregade. The car must be road legal, as I drive to the 'Ring quite often, although it is not an only car. I want to spend a max of £10k for which I want to strip the car, cage it, uprate the suspension and brakes. I also want subtle, so black with some type of standard looking BMW wheels, and de-badged and de-chromed. I wantubtle,RWD,Manual,normally aspirated and cheapish. Please any ideas or comments.