BOV's, although huge ones can have fitment problems in X's depending on the setup. (My Synapse bigass BOV doesn't fit in my X with an ETS intake).

Fuel pumps, but they require different install kits.

Gauges and what not obviously.

Boost controllers if it isn't something like a plug and play Grimspeed for X's.

 

If the valve covers fit, then I can finally replace my "PLASTIC 2010+" valve cover with a nice powder coated valve cover. WOOT!! let's find out if this is true.

 

There are a ton of shared parts between the ct9a and cz4a. Tons! Hell, even from Evo I-X there are plenty of shared parts. There are too many to list but when you need one you'll discover some parts haven't changed in 20 years from seals ball joints and bushings to front brake pads to the little spacers under the fuel rail.

 

This thing..
http://www.perrinperformance.com/mit...rs-pep-sus-40x

And as others have said, simple stuff, like wheels, lugnuts, shift knobs, front pads, and just about any universal thing- like manual boost controllers, etc..

Most parts are a no go though since it is a totally different platform..