Hello! New 5th Gen Member

[wurlycorner]

Brakes wise, I don't mind flushing once a year, and until I can grab my hands on some larger discs (I see ATR calipers/carriers with a 300mm setup thrown around a lot, but buggered if I can find anything) it'll definitely do for the time being. I theoretically could not blast it for a solid afternoon but where'd be the fun in that? ;P

You have options here:
You can fit ATR calipers onto standard H22 prelude carriers and discs.
Or
You can fit 300mm discs, using the ATR carriers as well. You can fit ATR discs but you ideally need spacers to bring the centre bore down to the right size for a lude - note the disc screw fixings won't line up either (just rely on the wheel boss/nuts holding the disc on). Since you have a 5g you don't need to get the ATR discs re-drilled to a different stud pattern (you do if you're a 4g owner).