[clawhammer]

Hi, I've been serching for a track car for a couple of months now. As I was driving home from work today, I noticed an 87 Rx-7 NA for sale by the road. They're asking $800 for her, she has 130k miles on her, new clutch, body doesn't have any rust. I noticed it was smoking from the back quite a bit, but it was white smoke. Outside it was probably about 45 degrees, and the car was cold. What is this from? Later on, I would be interested in doing an engine swa on this, putting an engine from a 95 RX7 with twin turbo in it. Will it fit? Do I need to modify the engine bay at all for it to fit? What about an Rx-8 engine? Will that fit? Is this a good deal for $800 (I'll probably offer $500)?