Let me try and add some "meat" to this thread with some dyno results.
It may well have 260hp Matt, it depends on what the previous owner asked for ie an aggressive map for power, or something milder to retain some economy, AHM and Gus and other's will custom map to your requirement but obviously there will be a limit.
The site does say 260 for the 210 spec engine but higher figures have been seen and I'll add a dyno to show. It all depends on the condition of the engine and the "tune".
I would also say Adie's dyno is actually the most honest dyno I've been on and is not optimistic.
On the topic of tuning boxes, I'll add a couple of dyno's of a tuning box called a P-Box by STEINBAUER I had on in the early days when the car was still in warranty. Yes some tuning boxes are better than others as said. This one controls the injectors not the rail pressure that the crude ones do. It was custom mapped on a rolling road by Steinbauer, it showed 252hp at one, 248hp at another, and 243hp on Adies, all on a stock engine turbo/intercooler/exhaust.
Here are some dyno's of the AHM "F1 Map" which was for all out power on a stock engine (dpf/egr delete) it showed a 56hp gain taking my engine from 206hp to 262hp, and 269hp with water/meth.
I went to WGT the very next day, they have a Hub Dyno. It showed 278-280hp with water/meth there.
Ok so different dyno's all showing different results with up to 10hp difference...no biggy, but you'l see Adies was the lowest figure and I believe the right one as I believe my 210 engine was making 206 to start with.
On the subject of going for even more power, well how deep are your pockets
Have a look at this video I did: https://www.youtube.com/watch?v=4oNn5Itp-JI
Its my car making 305hp with thousands spent on fitting an intercooler double the std volume, a 3.0 tdi Audi turbo with a larger compressor, 3" exhaust system from turbo to rear boxes no cats at all, hundreds of ours fabricating and fitting it all, and days of rolling road time. Against my old setup of "F1 map" (262hp) and a nitrous kit with 50hp shot that can be brought for a few hundred pounds (this nos setup dyno'd at 315hp at reddot rr, so would have prob shown about 305hp on Adies if we apply the above logic
Yes its too close to call in the real world but one "car" cost thousands to make that performance the "other car" didn't...the choice is yours.