Standard XP suspension is way too soft for semi-slicks, for the extra grip they provide in the dry. In the wet, they are generally terrible at clearing standing water so could be borderline dangerous in these conditions.
I have a set of semi slicks (Toyo R888r) for the Elise that I only tend to use on trackdays or for road use when forecast is 100% dry. I have uprated spring rates and adjustable damping as even on the Elise with standard suspension, the extra grip they generate just forces the suspension onto its bump stops with the extra cornering load which is bad.