Got a brand new Sram BB30 XX1 eagle Quarq from ebay for £460 with carbon tuned cranks.
Have fitted it to a titanium MTB BSA68mm frame!
Thankfully the BB30 had the extra long spindle for BB30 right variants. The 30mm diameter spindle was also a consideration.
Solution was purchase some Hope68mm 30mm Bottom brackets.
Had to machine one to fit in recess of drive side Quarq. Just skimmed a millimetre off the outside of the hope bracket so it no longer touches the Quarq when tightened. Can still use recesses for hope tighten tool so very little has been removed.
Added six 0.5mm shims to the drive side with lots of lithium grease.
Tighten to 45nm…solid, no play, free spinning… done well over 1,000km, no issues.
Quarq is faultless.