I'm not necessarily against using Best Buy as a resource, especially since I'm trying to keep things within a budget, considering I'll have to pay for
two installs- the initial one, and the one to return the stock stuff at the end of my lease in 3 years. If Best Buy helps keep the cost down, and I'm able to get decent stuff- and/or the install- a bit cheaper, so be it. Actually, got a very good center speaker there recently, the Andrew Jones Pioneer SP-C22, for a really good price.
Meanwhile, I sent a message to this garage that did an APR Stage 1 ECU upgrade on my old A4, explaining my situation and asking for a referral or two for a good car audio retailer/installer to consult with. But I would like to be as educated as possible before I talk to any pros.
I also posted a thread at vwvortex, a huge car forum, mostly about VW and Audi. Found some threads there as well talking about speaker installs in these cars, the door panels definitely get taken off, and the 6.5" speakers have to be drilled out as they are installed with rivets... thanks VW

. Haven't found out much about the tweeters in the A pillars, but I'm not hopeful that it's going to be a simple (hence for me, cheap) swap. This one guy said that he had the dremel out the ones in his Golf, and then weld the new ones on. Jebus.
Here's that thread if your interested...
http://forums.vwvortex.com/showthread.php?5981998-What-should-I-upgrade-to-get-better-sound-in-my-GLI-w-Fender-audio-...-Not-impressed.
Also, I really want to know the exact specs of all the stock parts, so I know how to match impedences, power handling etc....