1gencrx

Prototype 4th version:  It is a new casting with a one piece body:

When are they going to release them as regular HW's? Like a 99 cent car vs. a 2.99 car? Surely they will have other variants...

In 2016.

It looks like we'll get the 4th version of the HW Honda CR-X in 2016 as part of the Hot Wheels Mainline.

The previous 3 versions have been part of the adult lines at a higher price point and more difficult to find:

This opens up the possibility of the having a Treasure Hunt version the CR-X as well.

Primaflow was a pretty common brand.  It looks to be an Si muffler, should fit 85-87 CRX Si and Civic Si.

Here are the relevant pages from the jackson catalog:

I have a white one in Oklahoma.  Can ship, but it will probably be expensive.