+1 on doing the motor mount while you are in there. Disconnecting the hoses to the WP and thermostat make it much easier to get to the motor mount. Then lowering the engine a little to get to the motor mount makes the WP much easier.
When I did mine I did:
WP, 160 low temp thermostat, new Porsche coolant/distilled water 50/50.
I did not do the motor mount because it had been done relatively recently, but I wish I had.
I used a Pierburg WP but at the time Sunset had the OEM Porsche WP for only a few $$ more and way cheaper than anywhere else. I think the price has gone up a little.
I also did UDP at the same time.
If your mechanic will do it for $100 in labor that sounds like a good deal to me, and if you do a Motor mount and the labor only goes up a little bit more even better
