18 with a chute is fun. Good addition for fun sailing. I ran a 12.5' pole, was advised not to go more than 13. 12.5 felt right. If you don't want to sheet to the back beam, look for a newer design high aspect kite. The original SX chute was old style, too much foot to it to sheet anywhere but the beam. A newer F18 chute should have a shorter foot.

You can get the main stuff new and spend the cash, or you can shop the Tiger guys for used race gear that is still good for cruising and save a bunch. i just sold all my stuff for $450.

I didn't have a square top but I'm guessing that would be a great addition.

If you have the original molded plastic rudders, ditch them for some EPOs or a set of new racing blades. Expensive, but well worth the improvement in helm.

For those that say the boat is a dog downwind - your mast is raked too far back. Rake killed the downwind performance on mine. Mast all the way forward gave great all around performance. Only time to rake was when it blew big time.