Don't take this as bible, but don't non-SS classed cars go straight to ASP?
My other idea would be get an allowance for SS. The version you're talking about is basically the same as ours except way down on power, right? If both of those ideas are shot because "not sold here", I got nothing.
The ballast up in SSM isn't the worst thing ever, but you're going to need far more power to deal with it. (trust me though, when you do, the driving experience is tits.
Last thing first: the Series 1 car is quite different from the Series 2 sold in North America. Standard form was under 1600 lbs. (true to ACBC philosophy) with Rover K series engine (from MGF) at 118 HP, BUT: sport versions were 145, 160 and 190 HP. Still a bit heavy for my tastes (remember, I am coming out of karts but using this as an intermediate set of training wheels before I let my kids drive BMod at 1,020 lb.s WITH driver) but as close as I can come in a production car with the engine in the right place. Also, the early series 2 cars used that same Rover K engine (not smoggable here, thus why no Elise here then) - which is a bit fragile when revved or built to much over low 200HP range.
The way I read the rule book, if the car is not actually shown in a class, it moves to some catch-all or up one full range where it IS shown. BUT: since the first specific mention of the 1996-2010 range is in FP, I am not sure it can be moved into XP - catch all that allows ANY drivetrain, pretty much. I can not actually FIND AP any more, but with 280 pages of frigging rules, well, that's why I really need to hear from someone who has been around them through their development or can comprehend their bizarre intent.
Ballasting to me really IS a big deal. As I said, if I wanted to drive something that heavy, I would just buy a truck (or, sorry to say, a series 2 car - which is heavier than my steel VW sedans!!!).
Your power comments are well taken. While a 190HP Rover K is genuinely stock, and 230HP built engines are fairly common, it is not exactly a reliable or durable or even pleasant engine to live with. Nor is it eligible for stock classes as "not sold here". Honda K20 engines are very common swaps (and allowable in XP and DM) at 220HP stock and near bulletproof. (300++ swaps to Audi, Ford and Honda are also common in UK, but of course for SCCA rules result in HUGE weight penalties).
What I don't know is if I can actually GO to XP with a car listed in FP. That would stick me into DM. Not really that bad a place to be, but for crying out loud, we're talking about a street car. It seems as if nobody in the SCCA committees has ever heard of cars instead of SUVs when it comes to weight.