I will be putting a set of Eibach springs on my 260. this will lower the car about 1" so i am told. the question is wheel size. this is what I would like.

17x7 4x100 4.5 off 40 front

17x9 4x100 4.5 off 35 rear

Will these fit???

Not without spacers. Way too much offset for a Z. At least for the front ones. Rears may be close.

If you put 9" rims on the back, they may fit but not without massaging the fenders. The tire bulge will be so close to the spring you will not be able to "work" the car. Tire flex will kill you. If all you want is 'the look' go for it. Nice way to tear up tires and ruin the rear fender shape, IMHO!

thanks

What would be the proper offset

Search the site for offset, you'll find more than you wanted to know.