as far as your top speed goes, it might very well be 45, but it wont be 45 for long, those buses are extremely heavy and built to carry a load effectively through city streets on top of it…… i bet you its got at least a 5.13 gear if not shallower in the rear end, that being said, i think a more realistic “real world usable” top speed is a lot closer to 35mph……
i studied and researched these buses for 6 months while i was looking for what i was going to use, i settled on a step van, small, 5k empty weight, and with a big american v8 it is screaming going down the highway trying to keep up with traffic…..
lol, as it is, i suck it up, stay in the right lane, and do 45, it kills me, but i figure worst case is i get more eyeball time on the graphics(well, when they are done)
not to mention the fact that between 35, and 45 in that thing your looking at, will probably be the difference in 10mpg(if your lucky) and 3-4mpg……. i dont know about your area, but here gas is already 3.54 a gallon, and that makes an amazingly huge difference on operating expenses.
also not to mention parts and repairs, your not going to run over to advance auto and pick up a leaky wheel cylinder…….. small simple things like that will end up being huge logistical nightmares……
 
but…..to be totally honest about it, if there was one here in town, and it was in good enough shape, i would seriously consider turning it into a pub crawler on weekend nights, and a busteraunt during the day…..maybe even strategically placed concert/festival seating with an open kitchen downstairs