Your stock bridge has probably left a footprint in the paint. Anything smaller will reveal that.
I'd recommend that you look for compensated saddles that can be installed on the same bridge but have an offset to allow intonation.
BTW - I have a Bronco and there's no problem with the intonation with the stock bridge.
Someone correct me if this is incorrect - but I think these swivel saddles will allow you to move them for better intonation: http://www.allparts.com/BP-2126-008-...es_p_1058.html
You can see a photo of them in use here: Wilkinson Compensating Saddles for P-bass
Question is - does the thread on the mounting screw match? I don't know.