I heard somewhere that the Plus and late model QPs have 225/45 R16 vs the earlier 20VTs having 205/50 R16. is this correct?

Alos, is the "Plus" wheel wider than the earlier 20VT wheel to accommodate the wider wheel? If not, should I be OK if I mount 225s on my LE?

Yes, and no. 224/45x16's are absolutely fine on earlier 20vt wheels, and offer a bit extra rim protection, however that size is more expensive than 205/50x16

Cool!

Found a "never been mounted"-set of four Hankook Ventus Prime online offering me a saving of about 30% off from the 205s. I was looking at only swapping the rear ones from the beginning and I would probably keep the P-Zeros with quite a bit of thread-life on the front end initially.

Would it be alright to run 225s on the rear set and 205s on the front? What about handling? Would it look odd?

Also, what about noise levels and tramlining differences between 225s and 205s? Noticable?