Btw to go 4x100 is it redrillng or can 4x100 be swapped out?
Gotta drill. You can press the studs in and out between 100 and 108 (easy) if you want to swap for winter tires or just get another set of 4x100 wheels as they’re pretty cheap and plentiful in the aftermarket. There are adaptors but you’ll lose most of the weight savings with a 3/4” hunk of aluminum and twice the studs.
I did a write up a couple of years ago. Search 4x100 conversion, I think.
The other advantage with the 6ULs are that they are designed to clear really big calipers. I probably have close to .75” between the spokes and my Wilwoods which barely cleared my stock wheels