nice ride van.
trim tabs won't hurt top speed, or decrease fuel efficiancy.
there mostly for getting up on a plane quicker with a full boat{full of fuel, guys, coolers,gear, etc..}
and correcting list when underway.
if my boat is full. i'll put the tabs down, punch it, and as she's getting up on plane retract them all the way up.
then make the list correction.
so basicly when i'm up on plane there all the way up, and one or the other might be down say a 1/4 to 1/2 inch.
helps in choppy water too because you can lower the bow and put more of the "v" in the water instead of taking a pounding on the flat bottom 'cause you gotta raise the bow so you don't get wet.
bow lowered, engine trimed up, actualy lifting the boat. so you can go faster than w/out 'em, in rough/choppy seas.
and if you want to get crazy, you can take turns like a jet ski.
i put them on my 23 w/a and they helped out a ton.
boat held 800#'s of fuel so when it was full it would dog off the line, and if two guys decide to hang on one side of the boat all you got to do is push a button to level out.
that and tell them to stop walking back and forth
mike