I don't know, i would say my big cruiser is pretty darn quick with the blower on it.
I will also say that it's my personal opinion there is no way you could have a functioning turbo system that is even halfway reliable for $2500. No way! Unless you were buying a used one that someone already has all the ducting, sourced the turbo, the intercooler, the exhaust manifold, coolant lines, welded on a bung for oil return lines, ect....
If you are thinking about the supercharger and can financially pull it off, do it. I would say that it's probably one of the most usable mods i have done to the cruiser to make it very usable for LONG overlanding trips. There is no way i would want to drive the cruiser from NC to CA stock... at least not with larger tires, roof racks, RTT, extra weight ect.. If the cruiser was bone stock, then sure, but with larger tires and all the gear it's a slug. Being able to set the cruise control on the highway and cruise comfortably at 80MPH for 12-13 hours straight is nice.
I will continue out on the tight wire and say if your motor has some descent maintenance, toss on the supercharger. If you are going to have to rebuild it, might as well wait until you have to. Enjoy some power at first and if you blow the HG, well you probably were going to blow it anyways. That's is completely my opinion.