My W211 E270 CDI (EDC16) has recently been remapped by Celtic Tuning and boy, what a difference!
I deliberately asked for an economy-prioritised remap, rather than a power one, but the power is huge too. They reckon they can increase the 270CDI ECU from 177bhp to 230bhp and from the response in mine, I have no problem believing it.
All turbo lag has gone, as has auto-gearbox lag (you know what I mean) and the pick up is steady, sustained and smooth. My Subaru Outback had 250bhp but it was delivered in a huge chunk in the small of your back through a notchy auto box. The remapped E is fast, very fast, but so, so smooth.
Mpg has improved by about 9-11% (if I'm not playing too hard) which is great news too with BP Ultimate at 105.9p per litre up here. Just looking forward to Loire Valley wine trip in 2 weeks with long French N-roads and cheap diesel!
It took a while to get the appointment sorted as one of the directors has been in and out of hospital over the last few months, but the guy who did the remap was very friendly and explained what was going on as he did it and showed me the new map on screen, having saved 2 copies of my original map, just in case.
I would certainly recommend them and I got an amazingly good deal on the price (pm me for more info if you want to know more), partly because of having to wait but also for mentioning this forum. Although I doubt they would match the deal they did me, it's worth squeezing a little if you can!