Shicks, you won't know it's there when not in use...NO rattles, bumps or that kinda stuff...storage position very secure (older ones weren't as tight). Obviously get the Rip Tide (saltwater) version, definately 24 VOLT (12s weak)...mine's 74lbs thrust, they updated to 80lbs right after I got mine...AUTO-PILOT is great, STAYS on course while you're doin' your thing out the back...will come w/wired remote-control which is good..I got the Co-Pilot which is wireless and has up-sides and down-sides-$150 extra...figure on two group 31 Marine batteries and for THE REAL DEAL get an on-board charger to keep 'em hot...my Guest 2620 has been flawless for 7 years...
Shaft length...mine is 48'', but suggest longer for Chesapeake Bay use...in rough water it'll come outta the water and gurggle if shaft not long enough...54'' is standard...if seas are too high for that length, you'll probably be headed in anyway...
They offer a bracket for easy removal...mine's permanently mounted...good luck w/it...if any more questions, just holler!!... ;D...
They're MADE to get wet so don't sweat that and if you still got a bow-rail, you'll have to remove center section... ;)...
One more thing...you'll have to deal w/the nav-light on the bow...I split mine... :)...