I really want to get a full exhaust for cheap. I was thinking about getting the Gen 2 header, Danmoto Cat Delete/Gutted Cat, and the Two Bros Slip-on that's on my Gen 3 right now. What I'm really worried about is fitment. How would my Two Bros slip-on fit on the Gen 2 header?
I think it would be easier to buy yourself an industrial Mandrel bender for the garage and to custom make your own headers for this.
Seriously, going cheap and piecing a bunch of crap together usually doesn't give you anything except headaches and a lighter wallet. For all the parts you're looking at, why not just buy a header for the Gen 3? What is the purpose of you doing this? I ask that since a full header isn't a "full header" if it is stock and just has the catalytic converter removed and mated to a slip-on. There's minimal power gains, you already have the noise you want, and without a tuner hooked up to correct the fueling, you're likely to have performance issues there. So...more money and time wasted on a dyno to make it run right or gain any power.
I doubt your 2Bros exhaust will mate up perfectly. It should be close, but the outlet of the header is probably at a different angle and/or size (since the G2 exhaust is undertail and expected to mate to a y-pipe). So don't expect it to bolt up.
Hell, just drilling the cat from your stock G3 header would be cheaper and easier.