On this pic it has twin discs but doesnt look like the inverted forks of the GSXR that most do. Is it Katana forks?

yes, those are stock katana wheels same as GS just painted nicer from fact, and the rotors are diff from GS but bolt on same wheel. Kat 600 front end is spose to be direct swap out. the frames are very simular in design

Wonder what all was done for the swap, just Katana rotors and calipers and master cylinder plus the forks? Still looking to improve my brakes but have yet to replace the brake pads or lines so dunno if I even really need twin disc or not.

I blead the brakes on mine and it helped a little bit. Put on some SS braided lines and noticed a big differance in bite and feedback. Somewhat cheaper than swapping the front end and doesn't add any extra weight.