You can use a non-remote style exchanger that has the cap and expansion tank, as a remote system. You just need to add an expansion tank at the highest point in the system.

Don't do the raw salt water...it's well worth the effort effort now, vs the pain later.

The CP performance kit is as simple as it comes


https://cimg1.ibsrv.net/gimg/www.off...0653de6c6.jpeg