I never did get any good pics of the calipers installed, as my digital cam is junk. I actually fabricated a new hard line, with a 'Y' fitting that splits the line into 2, before it reaches the caliper. I bought the 'Y' from a local aircraft-type hose dealer, but they should also be available from Earl's, Aircraft Spruce, etc. I used brass, and I've been told that aluminum isn't suitable for such a task. There's plenty of room behind the caliper to work in, so bending the lines wan't a problem, and I had them flared by the hose dealer, as I've never been good with those ISO bubble flares. A friend used a few spare 'T' fittings from the rear brake circuit of a 115, the one that sits just ahead of the differential and splits the line for the two rear calipers, but I think a 'Y' makes for a neater install.
The BMW calipers are heavier than the stock ones, but I don't think that's a big deal, as it's not rotating mass, and compared to the entire unsprung mass, shouldn't make too much difference. I've got Cromodora Daytona replica's on the '74, and the stock star-center alloys on the '87, and there aren't any clearance problems on either car. Brake pads, hardware, and caliper kits are readily available, as there are plenty of 2002tii guys still out there. If one wanted to go one step further, calipers could just as easily be fitted from a 5, 6, or 7 series BMW, which have a spacer between the halves, to allow for a thicker, vented rotor, maybe from a Montreal. I don't think that's necessary for a street car, though, and can't recall ever cooking the brakes on a Spider.
Here's a link to an article about the caliper conversion, so I'll have to admit this wasn't my idea:
There are other options, too, such as using alloy calipers from Outlaw or one of the other aftermarket suppliers. Mike Valant is using Outlaw calipers on the front of his Giulia Super:
Andy Kress sells Outlaw kits specifically for 105/115's: