Will buying a g35 coupes OEM struts and springs lower my g35 sedan significantly and will the struts/springs fit directly on to a non sport suspension. thanks

No it will not lower your sedan significantly, only ~0.5 inches. The coupe suspension is a direct bolt onto a sedan (as is the Z suspension which will lower you ~1 inch)

i have a complete set of 2006 revised suspension from a 350z with less than 10k miles in perfect condition...great for lowering 1" all around...$200 bucks plus shipping...let me know

You may want to consider using Coupe springs in the back. I have a set I havn't put on yet, but most say that you get a more level look out of it. Mine is a bit lower in the back than the front with the Z springs all round.

I was told since I do not have the sport suspension (red) that I would also need to buy shocks/struts. Is that true?

I will say this, the shocks won't last long. Mine went a year and the backs were leaking like a sieve. I slapped on a set of TOKIKO D-specs and never looked back.

full revised Z suspension will give you a nice even drop, about 1" in the front and about 1/2" in the rear. You will need to swap out your non-sport struts/shocks since they are not matched handle the stiffer spring rates.