you won't be able to change suspension top bushes or remove nut holding strut into strut top may need a bigger hole in the strut brace to get a socket in, you wouldn't be able to get a spanner in and an allen key to hold strut either.
really thinking about it, don't weld it in.
what you can do use use nutserts, that's what i did with my mk2, i used M8 nutserts, hard to fit the bloody things, but hold it very tight.