^This.

It would look really strange to run just the sides painted. I've been noticing cars that have unpainted lower sills, and for the most part, if they don't have them all the way around (like the G) they have them only on the sides, or only in the rear.

I think the only part you could possibly get by with would be the rear unpainted, but that would only be a temporary measure, until you could do it right.

 

I wouldnt do the rear lip as I would just paint the lower sill (unless I found a Nismo diffuser). From lip not needed as I would just paint the lower air dam until I got my new front end.

 

I don't know why more people don't jump on the stillen rear being the nismo is discontinued. Is not ugly at all like the front lip is and has a nice difuser that can be painted black and looks much better than painted stock valance but their money their choice of mods.

 

I would hold off on painting the sills and get the nismo and put off on installing them till you get a front.

Once you get a new front, you gonna wish you had the nismo sides and you would have painted the OEMs sills for nothing.

I know it tough to be patient but i will pay off in the long run.