This is an issue I am running into as well, but plan on elevating in the Far future (i.e. about 2 years from now).
However, I am thinking that locally if the track is a short track (i.e. more turns than "straights") and you have plenty of seat time then you should be quite competitive in the local class. I mean on my "home" course we have a SS lotus elise that has posted the fastest raw times in the last two races we have hosted running Toyo R1Rs in the front and Star Spec Z1s in the rear, and that is against Nissan GTRs, Vettes, turbos, non-modified and modified vehicles etc... So based on track design I think the N/A could show it's weakness.
Other than that, i believe the N/A elise should be QUITE competitive in the SSM class, especially locally, Nationally...as Sprocket said...probably not.
2005 Lotus Elise Graphite Grey - Salvaged title started the SSM build!!!
Maverick ML8 - Other daily
2005 VW Passat Station Wagon TDI (harder to find than the lotus?)
2005 Lotus Elise Starlight Black - Sold