Some things you forgot to mention
- As with all things German, NEW washers are a must. That is, insert "new."
- MUST inspect condition of insulating plastic sleeve that fits between bracket/strap and the filter. Replace if worn out, fit one if missing.
In addition ...
I could do mine simply with right wheels up on a curb. No jacks, that is.
Nuts are removed, not disconnected. Wiring is disconnected.
Normally the "nut" built on to the filter is 19 mm and a 19 mm wrench is way better than a crescent. (Your writeup sounds like you didn't have this wrench.) When using way off brand filters, you get what you deserve in this respect, of course. Pretty much nothing German is ever 20mm.
Recommend the clamps.
http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=66783&group_ID=1461
If you're going to be so conservative as to disconnect battery and have fire extinguisher handy, well, why not continue it that mode?