what year and engine code? could be turbo and engine spec. small port head vs large port head, VVT, BBW etc etc
only turbos were k03, KO3s (slightly bigger compressor IIRC) and Ko4 (used on 225 TT's), they all run very low boost around 9psi
, different maps in various golfs, audi, skodas and seats. to make matters worse, VVT and DBW engines are all slightly different. Most tuners claim that cable throttle engines tune to a higher level bhp, what they really mean is they are easier to remap.
A proper tuner with a VVT and DBW engine will get a lot more out of it. (speak to Minhea at MRC if you want an education on that!).
You should look around all teh Revo and assorted remappers to get an idea of what is on the market, do your homework and speak to people who have actually had a remap done to their car (not seat of pants testing in a mates passenger seat!).
Most of these maps are just a reflash of the ECU with an existing map they have created based on your model car, if you have any mods like FMIC/Exhaust etc then the map won't be working to its maximum as they are based on stock cars normally.
They seldom include any rolling road time to spot any flat spots or issues post install, if you have any problems you can take it back and if not entirely happy they can remove it. just make sure you are left with what you had before!