RE: saito 180 to big for a funtana .90 ?
It will be fine. A lot of people are putting the 1.50 on it (including myself), which is sufficient. I wouldn't say the 1.80 is overkill, because I love power, but I think it may be the rule of diminishing returns. I hear the 1.80 burns much more fuel than the 1.50, and everyone who has the 1.50 says that it provides plenty of power (I've never seen that disputed). So, it will be fine if you don't mine forking over the $$$ for the fuel. Just watch your throttle and keep the speed low. Use that power for vertical pull, not lateral speed.