ive done it on mgp forks, swords and merrows for 120 then 125. mgp forks snapped in 2 days at the legs. my ics pair of swords are over a year old no cracks or bends but i changed to merrows which are 3 months old now to get the height of my bars perfect. most decks can fit 125 without cutting the deck, just make the brake. i say make one because if you find the right steel like i have they work better than any pre made one. ive had the same one for over 2 years on 4 decks. i did however have to shave ~1-2mm off the headtube in certain places (not as bad as it sounds) for a district to fit 125 in the front so dont use that deck unless you dont mind putting work in.
looking at what ive said i doubt most people are lucky enough to make parts last like that so just buy parts that are compatible, tsi makes it all (ex wheels) so support them