as for price, not sure,it was part of my total package, new 3830, bh90, 6' rear finish mower, 6' box and an auger. purchased late 2004.
now for capabilities:
i had a 2910 with the 4690 bh it did ok'ish. but this new bh90
i like a lot!! it seems to be plenty powerful and i run the engine at only 1500/1800rpm. ti took about 3 or 4 hours to get the hoe operating to it's capacity/strength.
now installation:
assuming you have the two lower lift arms already off, it only takes about 10 minutes to install. removal is even quicker.
hope this info helped.
beware.........you can not have a midmount/belly mower with the bh90 on a 3830!!!!! two major subframe members required for the hoe are in the way.
good luck
steve c.