a: I never said you were an idiot
b: You were going to be the manager of the aircraft so.... It implied to me the you were representing yourself as an "expert"
c: As for "however I have received conflicting information from a number of sources", that is why I would hire an expert consultant instead of writing a message in a internet forum where you really are not sure of who any of us are......find a guy who manages a flight department with King Airs or a Consultant or even someone that has verifiable references and hire them at a fee to help. After all this is a huge outlay of money for someone (and a reflection on your professionalism) - people get burned in this stuff ALL THE TIME!
Some C-90 info:
C-90, C-90A, C-90SE, and C-90B are the basic choices in the King Air "C" line.
Major differences are the older C-90s are slower, have less range, has a different engine (PT6A-20 vs. PT6A-21, implications there) and a lower gross weight (9,650 vs. 10,100). The C90A and up have a triple fed bus system and some other improvements, such as a more efficient cowl, better standard avionics and a quieter cabin. Yes, in short the C-90A is "better", and depending on the money the prospective owner is willing to spend the market is ripe with good C-90Bs right now.
A good C-90B, 1995 or so, average airframe hours about 2700, with up to date inspections (6 year gear overhauls, good time left on the engines, recent or good windshields, no damage history, and so on) should run about 1.3-1.45 mil. Remember that TAWS B (for part 91 use, 6 or more seats) will be mandated in March 2005 (I think that’s the date) and that, at minimum, will cost about $23,000 installed.
You could of course go out and buy a 1979 straight C-90 for about $700,000 – the average airframe will have about 7500 + hours and as PSL said “This capability doesn't come cheaply.” – meaning you get what you pay for with an older aircraft or any Beech parts for that matter. A gear overhaul can cost up to $40,000 + the down time. You can re-engine the C-90 with a couple of aftermarket engines, Blackhawk being one, runs about $400,000 or so. Windshields are about $7,500 each, you get the picture, by the time you find a good old C-90 and upgrade it to the level of the C-90A or B you still have an old aircraft that you have sunk lots of money into.
As I said before, good luck!