I have 2X Xeon E5430 quad cores, overclocked to 3.2 Ghz (Yorkfield generation) efectively they are q9770's
Currently I have 8gb ram if that matters, I have access to 16gb if needed...
Would it be worth while to try bigadv?
No, bigadv deadlines were changed last year, and the minimum core count was increased from 12 to 16 cores (or threads, the F@H software isn't too picky, it sees threads as cores).
You could definitely crunch some SMP though, should still give you descent PPD. I'd be interested in seeing your results if you do give it a go.