Originally Posted by
bikingshearer
Not a close call in my mind: get the spacer(s). I would not cut anything off that steerer - there is nowhere near enough margin for error in my book. Another advantage of the spacer: it lets you get the stem a little higher than if you cut it. There will come a time when that matters, even of it only a difference of a few millimeters. Don't ask me how I know.
Raising the stem higher by using headset spacers isn't a good idea. It's a false sense of security thinking that as long as the little max height line on the stem isn't exposed above the headset, you're good. I've seen people use fairly tall spacers to "enable" bringing the stem up higher, when in fact it may just bring the expander plug up into the threaded area. And I'll tell you how I know people do this - I've replaced several steerers with this exact issue where the threaded area was either bunged up or broken off completely. I even documented it on this site for a Paramount steerer repair for [MENTION=401497]RiddleOfSteel[/MENTION] who found the frame and fork up at the co-op he volunteers at.
Now a production bike probably doesn't have this issue, but there were plenty of replacement forks sold BITD with very long threaded areas on the steerer. This allowed a bike shop to stock just one replacement fork - a safety issue in my mind.
Now, with the OP's few mm of headset threads to cover, it's highly unlikely that this would be an issue, and I agree that spacers would almost assuredly be fine. I just don't want everyone having the takeaway that you can just put a spacer in without thinking of where the expander bolt will hit - and it better be completely below the threaded area.