I purchased a pair of KAD calipers to replace my Mini Sport calipers. Go here to find out why I had to send the Mini Sport caliper back.
I am not really qualified to comment on the KAD parts. They seem to be just as well made as the Mini Sport item. They do have 6 bolts holding the two halves together instead of two, but beyond that, I don't know what to look for in a piece of aluminium. The most important difference however, is the lack of a steel dust seal retaining ring. The KAD calipers retain the dust seals with a groove in the bore of the caliper.
In operation they seem to be exactly the same as the Mini Sport item. This is to be expected since they use the same piston sizes and the same pads as the Mini Sport caliper. Apparently the Mini Spares alloy caliper also shares these paramaters.
The only blot on my KAD 4 Pot experiance was that they were sold to me with the claim that they would fit 10" steel wheels. I tried a steel wheel when I first got them, and it didn't fit. I guessed that this might be due to a difference between New Zealand and UK wheels. I decided that even if they don't fit steel wheels, I would keep them anyway. I was (and still am) tired of brakes and couldn't be bothered sending them back...
It turned out that they don't fit any steel wheels, and even don't fit a number of types of alloy wheel. Luckily they do fit my wheels. I will shortly put up some pictures of the wheels they do not fit.
Anyway here are some pictures so you can see for yourself.
Notice the (silver coloured) spacers that go between the caliper and the mounting ears on the hub.
The silver mark in the middle of the caliper, which is actually in the apex of the A in KAD (which not really visible in the picture) is a special seal inserted after the calipers were anodized.
This is the metro vented disk on a mini drive flange. Some filing of the steering arm may be necessary. I also had to take 0.030" off the mounting flange on one of the discs to get enough clearance between it and the hub. Something in my hub is out of spec, if indeed, they were specified to within 0.030".