St220 To Buy Or Not?

Hello everyone I'm new to this forum but am looking for some help. I am in the process of buying a St220 2003. I have a few concerns but have left a small deposit for it but can't collect it until Thursday as New Mot going on. Now I'm at home I'm not sure wether to go through with it. The car has done 100,000 miles, Its had 8 owners yes 8 but it has a shed load of paperwork for New driveshafts, Disks and pads, Milteck Exhaust, Track rod Ends Loads more but can't remember it all.The service History is there but not all main dealer, Twice main Dealer and the rest independent last service was done at 95,000. On the testdrive the engine ran sweet had loads of pull and idled fine the brakes felt proper tight and the clutch was not bad felt abit weak but ( I'm driving a Toyota celica at the mo so maybe that's why). Letting go of the steering wheel the car pulled to the right? Said this to dealer and he said Tracking, Also once the car was warmed up I could smell Heat/oil from the car? Could it be a sump seal or something? Other than that it seemed fine there was a sound at high revs like a stone hitting metal or rattle occasionally at higher revs sounded like it was coming from underneath?. Brake fluid could do with changing. The interior Everything worked all electrics and looks nice and tidy like it's been looked after. I just don't know what to do now is 8 owners to many? Is the heat smell a major problem