The Savage was never catalyzed, not in Europe anyway, which is why Suzuki dropped it in the Old World. So buy a HD catalyzed exhaust and that should be one problem solved.
Another issue is whether your State will demand 'low beam always on', that is, you twist the ignition key and the headlight goes on; this happens only on Scandinavian bikes, not in Germany, Italy, France and other civilized places
So just hotwire the low beam relay to the ignition module.
Speedo in mph vs. kph is like asking if the bike imported from England has been converted to left hand drive
you just drive - at worst, stick little slivers of colored tape at 35mph = 55km/h, 55mph = 90 km/h, and 70mph = 110km/h. I doubt you'll be riding any faster than 110km/h, and if the speed's lower than 35mph just coast along at the same speed as local traffic.
... now, about those wind-down windows...
Maurizio