SSCOT = superspeedway.net COT mod?
That's what I've been using as well, and there is absolutely no difference handling wise between it and any other series that uses cup physics. What has changed is the cockpit view, but it's OK in the 1.04 version (somewhat similar to the GNS mod) even though I prefer the default cup one, and the frame rate is worse compared to the default cup series or the PWF mods.
This shouldn't be an issue for most people, however, I certainly use one of the slower machines around and still get 40/50 fps or more.

Having different physics in the COT mod is technically impossible as well, because the only ways to change the handling of the car would be:
1. Custom tracks with adjusted geometry, grooves, grip settings etc. - not the case here, the COT mod doesn't come with any tracks.
2. The use of a different series' physics, such as GNS, CTS or PTA - not the case here either, it's definitely cup.
3. An edited NR2003.exe - the mod doesn't come with one, it's just one folder that's extracted into the series directory.