The BMW guys do both the spacers and new wheels but the BMW wheels are nice, so most do spacers. And as much as 20mm with no issues. I have 15mm on the front and 12mm on the rear of my 2011 ZCP E92 M3. It must not be too bad to do as a lot of track BMW's run them also. If you think about it, it is basically just changing the offset of the wheel, much like if you had wheels made. To a certain point, depending on the way the wheel is designed, the offset would be set widening the same area of the wheel on new wheels as a spacer would, so I wouldn't think it would be a problem. Hell, just a 1/4" spacer on the front and maybe 1/8" on the rear would really change the look if the offset is staggered in such a way and you may not even need to change the studs.
The wheels on the TH can be rotated now, correct? Having spacers won't change that, but if you bought new wheels to get that same look, you could no longer rotate them.
2002 Honda S2000
2009 Acura MDX
2011 M3 ZCP
2018 Trackhawk (Rhino)