+ 1 For R-Tech
R-Tech rely on the likes of Graeme as they dont spend thousands upon thousands on advertising like other popular choices available in the remap industry. I would also like to point the OP in the direction because if you are new to this it is hard to see past all the sales & advetisement of the big names.
I've been to other tuners, which include Revo, Bluefin & Chipped UK (Viezu) (and more with other manufacturers vehicles) and I havent made the same mistake since. Unless you live a million miles away from R-Tech I would thorougly recommend you pay them a visit for the best customer service, the fact they actually do a full diagnostic check of your vehicle and provide you with a custom map to suit your vehicle.