Which side needs changed?
As above the n/s wishbone bolt fouls the gearbox to fit it the correct way, but most folks get scared about it. It is as simple as undoing 2 x 24mm subframe bolts and lowering the subframe a little, some leverage under the gearbox and out the old bolt comes and in the new one goes. Not a problem at all. By the time you cut out the old one, you could undo the subframe bolts and take it out properly.
I worked as a Ford tech for a while and never inverted the bolt, and never have since.
If the bolt is inverted the end of the bolt needs cut as it does fould the gearbox casing and I have seen it damaged.
Lots of people do it the other way, it's up to yourself, I will always fit it the way Ford did. But if you do fit it the other way and it does rub through the casing, you'll wish you'd spent the extra half hour dropping the subframe bolts all those months ago.
Also remember garages on bonus want to do the job as fast as possible to keep their efficiencies up, making bonus and money in their pocket and if cutting a bolt saves them some time.......
*MY opinion on cars I work on. Everyone is entitles to repair their own cars themselves.
All mk2 wishbones are the same except the ST200 (I used to own one)