I used these guys for the coating - http://www.cicceramic.com.au/. They are bike riders and keen to help. Mention you're from BMWMCCWA and they might slip in a discount.
They told me ceramic coating is best applied to both sides, which is why I removed the cat. Talk to them about the pro's and cons of ceramic coating the external surface only.
After 15,000kms
I posted the following a couple of years ago
I've got a 09 GSA. This is what I did.
1. Removed the cat from the OEM headers (search for athread on UKGSER by 'bluebird' titled Removing the Cat - or similar)
2. Got the whole system ceramic coated (bling purposes)
3. Retained the OEM muffler
Outcomes
a. Different, deeper note from the exhaust (as extensively described on UKGSER)
b. Breathed much easier and seems to pull better through mid range - modest improvement only.
c. Bike ran much leaner. Too lean IMO
So
4. Bought a Wunderlich Power Commander 2nd hand. Came with some pretty aggressive fuel mapping.
Outcome
d. Unbelievable improvement. This bike absolutely flies now.
e. Increased fuel consumption. Typical highway consumption pre WPC was 5.8l/100km; post WPC 6.4l/100km
So
5. Have backed off fuel mapping approx 500km ago
Outcome
f. Still a great improvement over standard. Bike still very quick.
g. Haven't refilled yet but dash reading is 5.1l/100km. I've never seen a number that low in over 27,000 on 3 different 1200's