Space is an issue too, I only have one location I could put the dish and as it is, the 80cm dish willl only go round as far as 28.2E maybe a smidge more eastwards, but after that the arm touches the roof of the house and won't go any further. Everything west of it should be fine though, nothing stopping it there. (It wasn't a problem when putting it in originally as all I wanted was 28.2E, but now the dish is set on 19.2E with 28.2E as an offset with a bracket).
The satellites I was most looking to receive via the motor were 28.2E, 19.2E and 1W, and maybe a few others, programme depending!
I think with the added size of the motor a larger dish might not be possible to put it in it's current location unless a larger pole is used or a different location altogether, but like I said, there's no-where else to put it really unless modifications are made, but that's going to push the cost right up and I wasn't looking to spend lots on this.
