Yep that is the kit you will want, the 24watt kit will work as will. Both kits comes with everything, you could possibly need. Except your basic wire cutter, phillips screwdriver. The only thing I would suggest getting is some heat shrink wrap tubing, they send wire nuts for connecting wires. They will work just fine, but a pack of shrink tubing costs $1 and will seal connections from moisture much better. Or you could use electrical tape. You do need to build a hood to mount it in. You can get directions for free with your order, they also have a couple different threads on how to build different hoods. The odd shape of your tank, will probably mean you will have to kinda customize a hood. I made mine out of wood. I'm not terribly familiar with fiberglass, If its rigid enough it should work. The ballasts are kinda heavy. They also produce a decent amount of heat, so make sure to provide ventilation. Overall its not too hard, the only electrical/wood education I had was back in the 7 grade.
If you want to get really snazzy you could get some cold cathode moon lights
. Cost about $8-10 dollars for a setup. Unlike the single LED on the current fixture, they actually make light. Your hood would have two cords though. The current fixture does too.
This is the 2x55 hood I built for my 55gal. The blue things are the cold cathodes. It's been running great for 6 months so far. It got pulled off the tank by a kid, needed some minor fixing. But it never stopped running and the bulbs didn't break. My wooden hood cost about $25 dollars to build(wood/spray paint/nails). If you build one, it would probably cost a fraction of that. Since most of the cost was the wood.