I'd look at Lenco tabs, good product and clean install. check this part number out 15049-101, $1000-1100 plus a led switch $200-250. Are they a pair of 280's no, but a very good choice and will serve you well, all electric makes a very nice clean installation only down side is the switch options all come in black. Since your boat is a 2000 same as mine the black will look very out of place at the helm, possibly disassemble and powder coat or hydro-dip. this would leave a nice downpayment for the hydraulic steering. If the price of the 600 is out at this point then you won't be seeing 80 anytime soon, as others have said 500-550 and a well worked prop will get you low 70's.

Isn't the general rule of thumb 1" of trim tab length per 1' of boat? So 27" long in the OP's case. The more I see of the Bennett auto trimming system the more I want to swap mine out for it.

Keith