Well, it's a lot easier now. In the past we had to cut open our FX ab plates and make our own little keyhole cutout. Now, most TK ab plates come that way out of the box. The diamond knee plate used to also be a "make" item, but now I think you can buy one too. The rest is all take-aways, e.g. remove the drop boxes, O2 cylinder, and shoulder bridges. Ensure you have a stunt helmet (which is easier now, as nearly all TK helmets come stunt. Back in FX days, you and to drill out that extra tooth on each side and get different helmet decals) with no lines in tears/traps.
Weathering can be easy if you go Braks Buddy method (e.g. using tempura paint). I think if I had to re-do a kit today, it's maybe 2 hours of work, max, and no drilling!