XtremeMDX

I have an OS, A Top(Novarossi based engine) and a Novarossi S5. The S5 is similar to the S3 except for the 5 port and Turbo but HP are identical. My OS and Top has the same HP and are both side exhaust and I can tell you that Top can blow the doors off the OS anyday. Tuning was actually easier on the Top. For some reason it was a pain in the #@% to get the carb to hold the setting on the OS. The Top was just more consistent and faster. If you get the S3 you probably will never go back to an OS, I know I won't. The Novas also respond very well to mods. Just remember these 2 motors were built for different purposes. The OS is more for the regular consumer with daily reliability as the priority while the Novarossi is more for racing in mind. Tuning the Novarossi is a little harder than the OS but it does not take a nitro expert to tune it. If you have tuned nitro engines before then tuning the Novarossi engine should be easy. The S3 will be a little harder to break-in compared to the OS. If you follow a few tips then you should be ok. The fit of the pistons and sleeve are really tight, it has tons of compression compared to the OS and the S3 will need a little more prepping before you start up the S3 the first time.