3. YES
4. i use Motul4100 semi synthetic... used to use motul6100 full synthetic, but can't justify the price difference...
5. i have bridgestone grid2 in 245/45/17... they came with the car in brand new form... that was april 2002, it lasted me since then and i went to 2track days with it... still got a fair bit of treads left... they offer enough grip for me..