Yeah I'm curious too!

 

I still need to do a manual cleaning as I don't think mine has ever been done. I've seafoamrd many times and it feels a little better after.

However, I just did two CRC cleanings about a week apart and it feels much better. I was having a problem with the car randomly pulling boost when getting on it through 1st through 3rd. Now it's pulling strong all the way through.

 

HUGE improvement especially form a cold start.

1) Before the blast when I started the car the idle would go up to a little over 1k then slowly wind down to ~800. Now it stays around 1000. It was never rough, stalled, or had trouble starting but the idle is noticeably smoother and doesn't bounce around as much.

2) 0 hesitation from a cold start. No flat spots in first or second gear before the car warms up. This was probably the worst and most annoying effect from the buildup. If the car wasn't warm you'd have to wait for extra room when pulling out in case the car didn't pick up like it should.

3) No intermittent flat spots in 2nd gear. These were worse cold but happened every so often when the car was warm as well. I haven't had one since the blast.

4) Throttle response is improved, acceleration comes on quicker and feels smoother all the way up.

5) It may be my imagination but the turbo blow off seems louder. I'm using the stock air box with a high flow K&N filter.

Very glad I did it. If you suffer from any of the above I'd highly recommend having it done. Car drives like it's new!

 

One final update: all the knock codes from my Accessport tune are gone! Originally I was running the Stage 1 TPS 91 octane map and had frequent knock codes so I took the tune off. I wasn't sure if it was bad gas (we only have 91 here) or the carbon buildup. After the blast I had a FMIC installed and today spent the last few hours testing the Stage 1 TPS FMIC 91 octane map. Hasn't thrown a single code and all the weird things it did before at low RPM don't happen either.

Carbon buildup has quite the effect on our engines!

 

I have a 2010 MCS Camden edition. Had the hesitations and glitchy performance issues at around 60,000-65,000 miles. Had the blasting done by Motoring Magic in Thousand Oaks, CA. Very experienced and knowledgeable shop owner. Car hauled *** afterward and still does now at 87,000 miles. I plan to get it done again around 100k.

 

I can't speak for the OP, but after I did my car there was a good change. I recently did it for a friend. He had a JCW and was running pretty rough at idle. The Valves were coked way worse then the OP's. After I was finished, it ran so smooth at idle I wasn't sure that someone has switched cars on me!!! This is hands down the best maintenance anyone can do on their N14!

 

I've got 78k miles and never had the blast done. I had a BG Injection service done about 2-years ago which amazingly made a slight different. Economy improved and power and responsiveness felt better BUT I know it's nothing compared to the proper walnut shell blast.

Anyways, I found a place that specialized in walnut shell blasting for BMW's and says he also works on Mini's. He's charging me $280 for the service which to me is a steal. I expect great things and will report back after my service next week.

For the record, my car is currently idling rough, and power feels very weak, almost like my turbo isn't doing it's job. I'm hoping this restores the new-car feel.

 

That's a great price! I bet it will make a very noticeable difference. I was well under your mileage and mine was full of gunk. Ask them to take before and after pics and post them!