Gus (Alfatune), Aide (AHM) and Adrian (Alfa Aid) apparently all developed their remaps jointly so you just need to find the closest to you. There is a fourth member of their syndicate but I can't recall who that is..
I was going to use a Celtic remap as I've always used them before and been very impressed -but as my car was already mapped by Gus when I got it... I doubt it would make any difference. Its really a standard General motors engine so plenty of people should be able to map it without too much trouble. The thing I like about Celtic eMotion is that you can buy several maps and put them on the car (or not) as you desire. So, my Leon has an eco map at 160hp and a trackday one at 190hp for example. And you keep the original so you can put it back when you sell the car.. its a five minute process to swap.