Trim Tabs for Seafari?

[McGillicuddy]

Saw a pair of 18x9 Bennett with motor and hydraulics, but no rocker switch (about $50 new I suppose). Dude wants 2 c-notes for them, and seems like a fair deal. I already have a Doelfin on 115 tower of power -- do I really need the tabs or should I hold off. I know it will be helpful stabilty wise and in countering mixed up seas but is it more nice to have than a necessity...I'm rewiring this thing and doing some cosmetic glass repair so I haven't even checked out its performance as is yet. Gas tank is also suspect, corroded around sending unit wiring and screws. Its about 56 inches long, can it be taken out without cutting the deck? Thanks guys. Happy Easter.