1: The parts
2: A welder (with enough wire

3: Patience (the more the better)
So I did it. With inspiration from Soarer and the knowledge that I finally got all the parts together, I decided it was time to fix my busted-ass exhaust. Following is a step by step w/ pics.
Step 1: Remove old exh, lay it out, ponder patheticness.

Yes, thats a stock turbo DP ghetto-mated (safety wired) to a stock L exhaust.
Step 2: Install downpipe w/ relocted O2 bung (Invidia catless, in this case)

Step 3: Attempt to fit welded cat&flexpipe, realize interference w/ carrier bearing, create and weld in offset.


Step 4: Hang muffler. For those who've not done this yet: Get an offset inlet muffler, it'll save two 90* bends and a moderate amount of headache and wire.
Step 5: Fabricate everthing between the flexpipe and the muffler.

This is where patience comes in handy. Be prepared to fit and remove about elevnty billion times. You should also be adding hangers in this step.
Step 6: Racing paint.

Step 7: Compare side-by-side.

Step 8: Get more wire for your welder and install tailpipes. Sorry I don't have pics for this at the moment (I'm experiencing technical difficulties, i.e. I ran out of wire, @5pm on a sat, while welding the muffler

Impresions: Its loud. I may get a resonator to install before the muffler. Boost comes on smoother and more responsively at part and mid throttle. At full throttle its really loud and actually feels slower, but that could just be my butt dyno overcompensating for the noise.
Hope this helps anyone planning this.