have a custom exhaust built. it will be cheaper than buying a vehicle specific one. 2.5" pipe, high flow cat (promuffler.com) no mid muffler, universal performance muffler (try borla or brospeed).

remove the R-16 resistor and run 93 R+M/2 gas (do a search).

consider a jacobs coil, controller, wires, and some bosch copper plugs.

that's about all you can do for cheap. anything else involves engine internals or forced induction.

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dew
86' 190e 2.3L 16v