Not that it helps but I have a 8120 with a Opti 225 and it works fine. However getting it to work was a nightmare.
Apparently there are two types of smartcraft and they are smartcraft and smartcraft (smart eh?) (in fact 1 and 2 but they are not called that - pure brilliance!)
Engines 2000 and 2001 are usually type 1 which is not compatible with the 2001 onwards smartcraft (type 2). I bought a 8120 after being told by barrus and navman that it would work only to then discover about the differences. After much mucking about and both sides saying they didn't know (their own products!) I found an excellent guy at barrus that asked me for the ECU no of my opti. This meant that in fact mine would work despite being the older engine.
All works fine now thanks the the pure brilliance of Kieron at ribshop http://www.rib-shop.co.uk/
- I also have another Navman plotter as a backup which is linked and shows all the gauges (cheaper to buy the plotter than the gauges from mercury!)
System is superb except that if you get an error message or warning (failed oil tank sender the other day) you keep getting error message every minute which cannot be turned off (unless you disable smartcraft) making the system a real pain. Imagine Windows telling you your antivirus is out of date every minute and that will give you some idea (only at 35kts).
BTW - Oil sender assy - Phoned around a load of Opti dealers who didn't carry it in stock. Phone Kieron at ribshop and he had one on the shelf, lent it to me to try and it works a treat - these guys never cease to amaze me, always helpful and know there stuff.