I wonder if it’s worth lugging around the BF2 for a while, to give you a baseline.
Then you can look at comparisons between the BF2 and other DACs (like @ProfFalkin’s RME ADI-2 vs BF2 comparison or @CinciJeff’s Yggy vs BF2 comparison ) to get an idea of what your SPL XE will sound like with those DACs.
If you want a Spring, you’re going to have to wait anyway, because the new Spring 3 won’t come out until April or May.