[vujade]

no you will not need to weld in the old holes.
as long as your drums are good and they are not totally worn
down on the inside, then you should be fine with having them redrilled.

the 4 x 100 pattern will fit inside your 4 x 130 pattern.

you will need to get press in 14mm studs at least 1.5" long if
you arent running any spacers.

I have 14mm x 2" studs, but I had to use a 3/8" spacer, thats why
I needed the longer studs.