RE: Tyres - Best tyres on the front or rear!?
Front brakes do ~2/3rds of all braking, so for me the front tyres are more important when doing an emergency stop. That's the most common emergency situation I've encountered, maybe twice in the last year (both in towns, under 30km/h).
In general my philosophy is that high quality part-worns will beat cheap new tyres every time. Currently running Continentals on front, Goodyear on rear.
RE: Tyres - Best tyres on the front or rear!?
I never skimp on tyres, it's the one thing between you and the road. Pirellis on the 630i, Continentals on the M6 and Goodyears on the 320i vert.
The Goodyears I think are best overall. Mind you the other two cars are pumping out a bit more power so might not be a fair comparison!