im not even changing mine back for service. i told the dealers and they didn't seem bothered
this is the attitude my local preferred vw garage have, i turn it off to deter the test pilots, lets be honest if you have a shed load of other mods on the car if you were betting man you'd put a fiver on it being mapped
The relevance of any modification (be it remapping or even changing the light bulbs) only arises when the modification is directly responsible for the accelerated wear or failure of a component.
My car has been in for stitching having come undone (unless you want to argue that's down to increased forces of acceleration unweaving the threads

), rubber door seals, a creaky drivers seat (same argument I suppose), a creaky boot lid and then the usual consumables (services, brakes etc). There have been a couple of items related to the engine which have required a little look but none of these have been directly attributable to the remap.
From my own experience I'd still take a standard GTI over any other hot hatch on offer just now - it just ticks all the boxes that I want to tick and in the order that I'd tick them - but a remap is definitely something I'd recommend. It has transformed my car and made it really feel like the hot-hatch I've always imagined the GTI to be.
Side by side a remapped car will be quicker than the standard but for me it's more about the sensation inside the cabin. The standard car in my opinion feels really flat and you need to wind the engine all the way up in order to get the performance. The mapped car by comparison is an anywhere-anytime kind of performer. It doesn't matter what gear or what rev-range you are in. There's just power!