There are several threads regarding removal of the ALDA on the 603 - one long one in particular made me decide it was ok as long as I wasn't too heavy-footed. I've never heard mention of a pyrometer, but that could just mean I did something dumb without enough research...

The AC actually works fine. It was converted to 134a by the PO (no documentation on this so I don't know if it was done correctly or not) and I would say it is adequate.

It has some effect on the coolant temp but it doesn't seem to be drastic. It does, however, drag the engine RPMs down quite a bit when the compressor kicks on.