I'm not yet an owner either. I go back and forth between the two... anic:
You can clearly get more power out of a standard Elise that is aftermarket supercharged. The Katana and BWR supercharger's both give around 50 HP gain with around 24 ft-lb torque increase. CharlieX's supercharger (still pending release) is reported at a whopping 85 HP boost with boatloads of torque (and it's Air to Air intercooled!). And the turbo option is always there as well; although most seam to suggest going the SC route with the Elise.
So with a regular Elise at 189, that would give you 239 HP versus the factory Elise SC's 218 HP. At 1 HP for every 5 pounds of added weight, a 20 HP difference is clearly noticeable on the Elise. And CharlieX's supercharger would leave you with around 274 HP - I can't even imagine that!!! And even brand new, your saving quite a few bucks going Elise with aftermarket SC.
1) You lose the warranty on the drivetrain, etc. as soon as you slap on an aftermarket SC and reflash your ECU.
2) The Elise SC does come with a nicer dash and that cool rear wing (OK, I don't like the wing personally, but some people do).
3) If you go standard Elise, then you can get an '06, '07 or '08 and get pretty much the same car. So pre-owned becomes an option. While the new Elise SC isn't really available pre-owned just yet (or at least, not many of them).
As I have learned from this forum, MANY people here will point out that driving skill outweighs horsepower a million to one. So having the extra HP in either the Elise SC or aftermarket SC may only get you to heaven faster unless you can handle the power in a car with no true stability control. Cornering is not the same as with a current production Jap or German car with stability control. The Elise is a true enthusiasts car and drives like an old British racer. I will get traction control as an option only because it has been recommended in many threads to help improve road handling in wet conditions - and I will be getting mine as a daily driver (of sorts). But Lotus's traction control is NOT stability control; don't confuse the two.
My plan is most likely to go for the standard Elise and enjoy it for about a year. Let all of the kinks and service issues sort themselves out and then add a supercharger at about 12 months. That way it will almost be like getting a new car at that time and I will be VERY comfortable with it by then. Truth is, I'll probably get it supercharged WAY sooner then that; but it's a good plan for now.
I have a buddy who can't get past the warranty thing and is going for an Exige S or 240S to get the most power he can AND maintain his warranty.
I hope that helps. I look forward to hearing other's input as well. opcorn: