You will be happy with the performance you get out of the Saito 100. I have one on a world models velox and it has unlimited vertical and flies very good. I use a 14x7 or 15x4W if I can find them. My extra with the TT 91 flew just as good as the velox with the saito 100. The TT may only be a 91 but it will turn the same prop at the same rpm as the Saito 100. This engine really likes a 14x6 or 14x4W APC prop the best. I have tested them several times and so have alot of other people on RCU. Believe me this is true. The TT 91 is also the smoothest running 4 stroke that I own. it will idle down real low and does not shake the plane when at idle. The throttle response is great also. The TT takes longer to break in than all the rest but once it does it is real sweet. Most people don't give the engine enough breakin and expect to much right out of the box. It takes around 3 gallons of fuel to get them where they are producing really great power. I have around 300+ flights on mine and it runs really strong. I wouldn't trade it for anything else in that size. I also forgot to mention the OS 91 I also have one of these too. I have it on a H9 ultra stik 60 and it performs great too. It is not as strong as the TT but runs very good andnever gives me any trouble. The only time the TT has deadsticked on me is when I am having too much fun and run it out of fuel. I have done this a few times. I still think that the best bang for the buck in this size of engine is the TT. If you like the quality of the Magnum take a look at the TT it is much nicer. I have both and the TT is just built better IMO. Don't get me wrong I love the magnum and it has performed very nice on my 4*60. I have around 200 flights on it with no problems.

Rick