Those calipers should clean up ok, though if you want them to look as-new, they'll need sanding back and respraying. Fun, fun, fun!
Looking at the needforspeed site, I question whether they truly include the discs and hats together. It would appear so. However, that's how it appeared to me too, when I purchased from ricambituning. Plus, they hadn't sold a set before, and didn't realise the price and part number (KRD0038) was for only the discs. So, double check, triple check, the price includes the hats/bells (which in turn includes the bolts/nuts). For the price, I would only expect the discs.
I don't think I had the option for floating discs; only 2-piece non-floating. I didn't research too hard, but I couldn't see an advantage for a street car. The floating discs allow for more heat expansion, which would be beneficial on a track car. Plus, I was concerned about how often - if at all - they require rebuilding: stripping, cleaning, and re-torquing the bolts/nuts/washers. It's probably ok, and not an issue, but nor was it something I had to decide because Tarox didn't offer a floating setup.
One piece cast discs would definitely have been cheaper. But who offers them in the right diameter? Whilst I didn't search high and low, the Tarox 2-piece brakes appealed because they were somewhat 'off the shelf' (even though they were made-to-order), and were a direct bolt-on fitment with no additional faffing around. If there is an off-the-shelf 330mm diameter 1-piece disc that fits straight onto the 75, that would be a good option that you'd expect to be cheaper.
Adapting a pair of GTA discs should be cheaper than the Tarox ones I have. But you need to find a machining workshop with experience and specs to reshape them to suit the 75.