I would be looking at the UCE engine with disc brake
Which is more tuneable the UCEOr the carbed pre UCE engine.For the carbed version up rated carbs are available to improve the fuel/air ratio after an exhaust and filter is addedHow is the EFI changable to suite these bolt ons
65 is possible.Don't cruise too long at anything faster than that.
+1 Opinions may vary and there have been a number of threads on this subject, but these bikes just don't fit that 65mph plus range very well in my opinion. Guys do it, but honestly there are way better machines for that application. These bikes seem to like to 50-55mph roads and will do those all day long without issue. Once you creep into the 65-75 mph range you are really pushing this motor, modified or not. A guy I work with smoked his 2011 B5 riding I-90 at 65mph with bags and a backpack from Spokane to Seattle - about three hours in the motor started knocking and it was done. On the up note, he rebuilt it and spent some quality time doing so and his bike runs like a Swiss watch now...
By my calculations, 65mph in top gear is about 4000-4100 rpm.This still should not be pushing it too hard from a piston speed view, but we still need to note that these things are not created equal internally at the factory. Some might have some weaker spots than others.