Hi Rex
Opposed piston calipers have a much better pedal feel than floating calipers, brand new or recently serviced floating calipers can work well but tired slide bushes and corroded pins and the fact that the single piston needs to deal with all the braking just means you don't find them on many race cars...!
The split in piston sizes is to give some feedback, the small piston will deploy first giving initial bite and a positive pedal and the bigger piston will provide the depth of braking, that said we're talking fractions of a mm here. They re also staggered to avoid pad taper. The 996TT takes this to the next level with 36/44mm pistons which give a great pedal and a lot of pedal in reserve
NQS has many benefits, pad choice, light weight and a great pedal. They'll also give great performance over a long time where the OEM setups do wear out if not serviced.
Used to break my heart people hanging S3 setups from £1500 quids worth of KW's finest
In addition they look great and give you a step up from OEM without the £1200-£2000 price tag
I had a guy drill his own discs a couple of weeks ago, this is the sort of guy this kit would appeal to, yes people can buy all the stuff of me such as refurbed calipers, NQS Discs but I envisaged people having a go to keep the costs down?
pad area just improves heat headroom bigger pad doesn't mean better stopping, you shouldn't underestimate the weight of big pads.....