Three random questions...

[Curious Joel]

I've got three questions:
1) I put my summer wheels/tires (the ones that came with the car) on yesterday. Since I did that, the car feels a little less stable on the road.. More floaty. It sometimes feels like the road is steering the wheels, because they grab. Why does it do this? I've got Goodyear Eagle RS-1 tires on it.. They don't seem that good... I'm getting new ones anyway, so it doesn't really concern me all that much. But I'm just curious (har har) why the car does this. I noticed it sometimes in the X5 too.

2) How does the service indicator count down both mileage to service and mileage to oil change? I was thinking of it today. On the E46, instead of the green bars it has a mileage count. Mine is around 11900. Is that to the service or oil change? It doesn't say.. I know BMW sets the oil change intervals insanely high. That brings me to another question...

3) I need to get an oil change soon. I have an independant BMW service place literally right down the road, and I've got the dealer >45 miles away. If I had it changed at the independent place, would it screw up the intervals, etc.? BMW reccommends something like 15,000 but my dad says every 3,000. Would that screw with the service interval computer? This is all very confusing to me.