I purchased a new 2009 M35x from a dealer in NJ and have been the sole owner.

Recently I was having the control arm replaced at an independent repair shop. When they ordered the 2009 OE lower control arm it didn't fit. They doubled checked everything and showed a pic to the supplier and they said it was a 2008 control arm.

How does a 2008 control arm get into a car that is sold as 2009 and the ViN says 2009? What else in my car could be 2008 and did I get scammed? Are there easy ways to tell a 2008 from a 2009?

Open the hood and look at your motor. Does it have 2 air intakes? If yes, it's an '09.

Check the door/ door jamb sticker to see the production date.
You probably have an early built 2009 (somewhere starting from about June/2008).
Many parts can be modified, changed, improved etc. during the course of the model year. This may trigger a new part # for that item.
I have an early built 2006 M. I notice more than a few part # changes for various components noted in the Infiniti 2006 parts catalog.

To see if your car has a changed out part # for a particular component according to date build, Look up that part in a genuine OEM Infiniti parts catalog. Be sure the catalog you are using is current, or at least print / publish date is after your vehicle build date to reflect the changes up to that time!

My mechanic checked that sticker and said the car was built in 2008.

What I don't understand is why my "2009" car may be inferior to other 2009 cars with different parts.

Seems like a bit of a scam to sell a vehicle with a 2008 suspension as a 2009.

I think it's your independent repair shop that misled you. The suspension parts stayed the same throughout the generation from 2006-2010; perhaps with a few revisions during certain years, but still visually and functionally similar.

My guess is that they bought a RWD control arm by mistake, and found that it wouldn't fit your AWD model. Otherwise, a 2006 AWD control arm looks like a 2007 or 08, 09 and 10 AWD control arm...and the same for the RWD vehicles.

I doubt Infiniti was out to scam you, but if you provide the part numbers of the Indy shop's original "2008" purchase as well as the newer "2009" part, post them here and we can verify their claim.

Thanks! I bet that was the issue because the shop guy said the 2009 had no separate designation for the RWD vs. AWD in the ordering system. When he did the reorder for 2008 he could designate AWD.

208,000 miles and still running great!