I didn't buy any engine from SOY.

I run the car on the track, wet and dry, and it's the stability and response of the Bridgestones that really impressed me. The car itself had then only 121PS (last season).

The good thing about the Potenzas is that they give amazing feedback. When driving on the edge, they just start to sing nice and early - you get to know when they start to complain long before they lose all control. It gives you a higher safety margin. They are super responsive, and really grippy in both wet and dry conditions. They never aquaplane, and dont follow tracklines in the road.

I have sorted camber front and rear with polybushes and rose joints, which I'm sure plays a big part in the responsiveness.

They wear well - I did about 80 laps of the ring on one front set and daily driving as well. Price wise they are OK.

The Ring-Mini drives on them too. He thrashes the pants off your average 911 and M3 driver regularly!

http://www.ringmini.de/

They may not be what your looking for but as a tyre for daily driving as well as track they are great.