I haven't but, I just got my first custom tune from Johan over the weekend (tuned me on a Sunday!) I was extremely pleased on how communicative he was, walked me through (he sent me .doc file and i read up on everything) Installed the tune to the car, drove around like a grandma for some errands and parked it. 2 hours later had to go to the next town, on my way back Lets just say i floored it and my hat flew off to the back seat. Car feels much stronger than ever before. Every tuner is a bit different, who you pick won't matter, What matters is how much more desirable it is to drive the car now.
Thanks Johan for the tune.