Hi Donald.
As Roger-Cheshire says, I've had my Sigma remapped by a well known Gloucestershire dealer (ask Chunky).
I find that the engine revs more freely in 2nd and 4th and in 5th there is no real need to change down on a hill. Fuel economy is still around 45 mpg (I don't tend to push it too much - just the occasional blast round some favourite corners) and keep to an indicated 77 mph (70 on SatNav) on the motorways.
I'd certainly do it again if asked whether I wanted the remap done.
Hope this helps. PM me for more if you wish (I'm not an expert so cant tell you if LSD is better - indeed I thought that was naughty powder until reading an earlier post!)
Cheers
