The SMP client will run fine on a 2 core system, but not every dual core can make the deadlines. My E2180 in my server can't make all the deadlines, which is why I went back to dual uniprocessor clients. Because of the problems with the Windows SMP clients as well as the deadlines, I run uniprocessor clients on my E8200 too
My E8200, which is 2.67 vs 2.33 in your case, can make the deadlines as long as it's on for at least 6 or so hours per day. The SMP deadlines are a lot tighter (I think 2-3 days) than the uniprocessor clients, and also often require more setup and maintenance.
If this isn't a system you'll be looking at constantly, go for the easiest option - two single core clients.
If, on the other hand, this system is on long enough to make deadlines and you don't mind investing the extra time, go for the SMP client. I find that two uniprocessor clients on my E8200 make about 900ppd (theoretical max, if it was folding the same units 24/7 uninterrupted) whereas the SMP client made around 1400. My E2180 makes 500ppd with two uniprocessor clients and 900ppd with the SMP. So, SMP clients do crunch quite a lot better, but require more maintenance and resources.
Hope this helps.