I believe all G35 RWD coilovers fit the M35 RWD vehicle.
The price of crappy ones are about $600 I think last I was looking, and good ones start about $850. Overkill ones that are "true coilovers" are $1500+ If you were to get true coilovers then you can also remove the rear spring bucket and replace it with a stronger single piece toe arm/mid link.
If you do plan on lowering the car more than a 1/2" from stock with the coilovers, you will need both front and rear camber arms replaced to allow for a larger adjustment if you want to keep wheel alignment correct.
https://coiloverdepot.com/collections/i ... facet3=M35