Pimp my Polo!

[LongLiveTazio]

Well, not really. But I was just messing about on a few websites and some reputable firms are claiming that remapping my 1.4 TDi (75 of the finest bhp, ladies and gents) will result in potentially a 20bhp+ increase and even more significantly rather a lot more torque. Now, it's never going to be a great car in the corners, but for motorway type overtaking and coming up to speed and whatnot I can see the value in it for a few hundred quid. Anyone had anything similar done to a rather mundane car? Are those gains realistic?