I am thinking of buying a Naish Mutant 5'5" used from a guy down here in South Florida, I am 145lbs, 5'10":

Is this board too big for me?

well, it depends on how you ride...

I will be riding a 8.0 Ram Air "Airbliss" kite in 10-20 knts....

I'm still kind of a beginner, I can go upwind on my toeside, but not heelside so far on my converted surfboard with straps...

it is a good choice.
Since I don't know the power of your kite I would also concider a smaller board.
It really isn't much of a difference switching to a Twintip of maller size.
A 151 or 144 board would do as well.
If it has the right curve, it will work with not too much power as well.
Depending on how good you ride and if you like the style, I wouldn't waste time on a directional anymore. You will improve so fast using a good twintip.
Will you be at the masters in Miami?
If not, come down and we ride for a while and I show you how good these types of boards ride and even for a little bit advanced rider it is now problem to ride on it.

Cheers
Toby

Yes, I'll have to check it out!
That would be great, I'll be there....

ok, I'm deciding between the Naish Mutant and a 2002 Jarvis Skate 157 board from slingshot, the slingshot is cheaper, too....smaller for my weight,,,Im torn
Lates!

the skate looks nice.
I'm interested in testing it, since I want to know what the additional fins will bring.
Still, IMO a good board doesn't need extra fins.

I just ordered the Jarvis, I'll bring it down so you can try it out in Miami!!

cool, I would love to.
Just heard that Robby won't be participating in Miami. So won't other guys from Hawaii.
But maybe they'll change their schedule.
Otherwise we have to rip South Beach!