1-Did you bypass the infinity amp or run the radios output to it?
Run through it. It has the 6 Channel setup for the dynamic tweeters.
1a-What advantage would there be to doing this?
1b-Could I not just slave the dash tweeters from the front speakers with a cross-over?
If you want, but it's wayy more work for no gain.
2-Did you install a parking brake bypass?
I always do.
2a-Did you use a switch or relay?
Either works. relay is automatic. It's up to you.
2b-Does it make a difference in phone dialing?
Yes. You can only diall from address book when not bypassed.
3-In modifying the sub-dash, do you find the bezel stays in tight?
I made my own, but yes it does.