There's a sexy Husqy 450 SMR on kijiji at the moment. It would match my 250 well
Keep posting, I'm curious to know if a twin is better than a single. I'm sure weight-wise a single will out perform.
Scott's (my old) Husaberg is just as fast as an SXV 5.5, I've ridden both. Except, it's a single with a carb which is much easier worked on than the Aprilia twin. I researched the SXVs thoroughly as I almost bought one twice. The orange sealant IS a problem. Hence, if someone were selling a bike with orange sealant, in my mind it would not be worth as one that had the black sealant between the cases.
For a race bike, you're gonna have to pour a lot into maintenance regardless which high end supermoto you buy. If you want something that's quick enough but moreso a street bike I'd say get a KTM 690SMC, they're a lot of money but seem like a pretty solid overall package. Thus far I've had four different Supermotos:
DR-Z400SM - The beast, I loved it.. Rode it on the street and raced it (out of necessity) handled amazing / stable (mostly because of the weight). Spend a few bucks on the carb, pipe etc and it feels faster, and doesn't ever really break
CRF450R - The animal, wanted to kill me most of the time. Fast as hell, tougher to setup suspension wise as the forks are for MX - was never able to get rid of front end chatter - keep in mind my suspension internals were stock
Husaberg - Ran my fastest laptime (for a supermoto) ever on it, without touching a suspension clicker - on street tires. The best overall track bike, not so fun on the Street
WR250X - Slow, well stock DR-Z speed, and prettier. EFI so don't have to mess with carb. Great daily commuter.