First off, disregard the specs on the 'change website; they are wrong.
Real Specs:
K2001 - Bore: 20mm (0.788"), 4th-5th valve 21mm (0.827")
Bell diameter: 495mm (19-1/2")
Height: 95cm (37-1/2")
Pro2000 - Bore: 20mm (0.788")
Bell diameter: 470mm (18-1/2")
Height: 90cm (35-1/2")
Pro2000: funky Ab on top of the staff. K2001: Open C above the staff 1/4 tone flat.
K2001 is VERY ergonomic. Both are a very conical design. Both horns are sized between a (real) 5/4 and 6/4 and do NOT have that "foghorn" sound that some BAT's are notorious for.
Either is MUCH bigger than a D.S.
Completely Honest Opinions on my personal K2001:
Plus: There is enough clarity, focus, and color in my K2001 that I would not have a problem playing it with a smaller ensemble if necessary, or even the right quintet. The intonation excepting the "middle C" is not perfect but very workable. "Middle C" tunes fine first pushed all the way in instead of open. The horn seems to be well constructed and the brass it not excessively thin as some notorious D.S.'s were. Valves are very smooth and do not hang up (tolerences are not the extreme Yamaha look-at-them-funny-and-they stick.) All tuning slides move very freely without extensive aftermarket work. Leadpipe and entire valveset can be removed for cleaning or repairs. Long pull on 4th slide available, all slides except 5th very accessible. Huge Rotax rotor blows very free, as does extremely open wrap fourth valve. Horn is very responsive and requires minimal effort to play, but can take everything you throw at it without breaking up - the best of both worlds. With the trend towards "small 6/4's" (i.e. PCK, 6450) this horn should be big enough for any application.
Complaints: 5th slide cannot be manipulated while playing without having a pullrod added. High C unusable open. Despite factory water keys water still accumulates in third slide requiring a pull-and-dump. Valves not factory vented. High register will start to go flat if you "relax" too much up there. Makes people think you are loaded because the horn looks like it cost $30,000.
My KaliBAT:
