I have an '85 CA coupe and I just swapped the intake and exhaust over to the federal parts. They were super cheap and I think look much cleaner on the engine. I did retain the CA air filter because it is definitely superior to the federal even though the filter units are pricey.

The stock turbo fit just fine after rotating the compressor c housing. The only new part I bought was a new exhaust downpipe from the turbo. My old one was too rusty to cut and weld.