I used GDL and had nice service (maybe a bit slow - but super nice to talk to).

One thing that I REALLY liked on my 84 300sd is that you can send in both the under dash brain and the underhood actuator and they can bench test both units together. Before you start swapping / buying parts you at least will know what the heck failed!

I had my unit worked on programa thinking it was the brain - found out later through GDL it was the actuator.... lesson learned!

__________________
~shell
As of 2/2010:
2001 CLK55 0o\=*=/o0
13.6 @ 106mph
10K mi
1984 300SD
260K mi and going and going...
97 S600
46K miles
1991 Sentra SE-R (extremely dorked with)
www.se-r.net