GJ nissanguy.
no worries on the t-taps. i use it all the time with no ill effects.
also really no issue going directly to factory wiring. it's just easier to revert back to stock if you use one of these metra's, or change HU manuf. later on.
with the pioneer harness, ive gone from 3100DVD, 4100DVD to 4500BT using the same pioneer harness.
here's the harness if anyone else is doingin install. for my 09 (non Bose) i use Metra 70-7522.