Thanks for the reply. So, basically I either get Quarq in GXP to keep everything the same and known compatibility, but accept that the spindle isn't quite as good as 30/Shimano, or I get a Wheels Mfg 30 to shimano conversion and add a couple spacers to get that spacing between the brake and the Stages (or Pioneer or 4iiii) unit. To your knowledge, is the Shimano spindle long enough to accommodate for 2-3 mm of spacers on the non-drive side? I spoke to the LBS about it and he kinda shrugged saying he doesn't know until he sees it, but obviously if the spindle won't allow for 2-3 mm of spacing I don't want to drop $1,000 in to a R8000 PM just to find out I can't mount it on my bike.