Well I have had mine done today. Took about 45 minutes and was very painless. Results were noticeable but not massive. Main difference seemed to be the smoothness. The engine seems a lot smoother and cleaner on pickup all the way out to the red line. I'm not sure my engine was that gunked up anyway as I only ver use premium fuel, it is serviced regularly and it's only done 46k miles. I will get it done every year now though as a good part of the annual preventative maintenance.
