I'd advise you not to get a map to keep up with your mate. It's not a game of who can outdo the other. He has 4wd so will always jump you off the line. If you are getting a map then get it because it will enhance the enjoyment of your car. Otherwise, youll feel a bit silly if you get a map and then find your mate has got a map aswell and can still beat you (or has bought a faster car)
Just about every company AMD, Superchips, MTM, Revo etc offer a map that takes the mk 6 to around 255-265 bhp. There are other posts on this forum about the pros and cons of each firm. It's really personal choice.
I know its tempting to want more power when in a rivalry (especially between friends) but be careful you don't ruin the handling and balance of your car.