Hi Clacker!
Regarding gearing. I'm currently running 3.07 in my 240D with a stick. Its a tad high for a standing start but not bad, and it drops about 600 rpm off my cruise rpm IIRC which is really nice. When I ran it with the automatic, the 3.07 gears were no problem, and still lowerd the cruise rpm nicely.

However, I would not recommend going to higher gears unless you are planning to modify the 616 for more power.

Cheers,
Chris