S8 V10 Carbon Cleaning

[Turbo Tony]

I didn't want to veer the transmission (saga) thread off to a tangent, so I thought I'd start a new thread about carbon cleaning.

My car runs a little rough in the mornings and I'm convinced that engine has more to give, so I suspect it suffers from carbon build-up. The terraclean definitely helped, so it's only logical that the backs of the valves, where terraclean doesn't reach, should be equally gunked up. First things first, does that sound like the symptoms I'd be experiencing if there is carbon build-up?

Over the past couple of days, I've been asking around a few places for what they charge and their preferred method of cleaning. I've contacted:

MRC (web form) - replied with quote
Unit20 (web form)- replied with quote
Vagtech (web form)
VW Audi Specialist Centre (facebook)

My second question is whether anyone has any experience with any of these places doing a carbon clean?

Question three is which method you think would work best? Both garages that have replied so far have preferred the mechanical approach. MRC will do the walnut-blasting method, but say that mechanical scrubbing works better, especially for the backs of the valves. I can understand the thinking, but the pictures I've seen online make the walnut-blasting look a lot more effective than the manual cleaning. I was hoping someone would tell me they blast with walnut shells and then manually clean the backs of the valves.

Finally, I'm quite tempted to try it myself... especially after Del offered to do mine for me (at least that's the way I read his post!). Of course, the cost saving is significant but I also may be able to have the inlet cover powder-coated. Mine has a small scratch that bothers me more than I'd like (no surprises there!).

Has anyone else done their own? How long did it take? Did it require any special tools? Any pitfalls?

If there's anything else I've not yet thought of, please feel free to share.