You can put spacers under your bar clamps to raise the bars. The rentals will take out some of the vibes of the b6 and give a better feel IMO. Not sure about bar ends for the pro tapers though.
Bar ends will not be much of an issue. I can machine custom bar ends if I need to in the shop but I think I would use some sort of hand guard as a bit of wind/rock break.
I can get pro taper style bars pretty darn cheap, cheaper than a good set of spacers/risers. The big cost will be the longer lines either might need for the brake. I will probably just do stainless lines as I already have a stainless rear brake line.