not sure if this has been asked before but here goes...

is it true that just a remap alone can add 20bhp to your car? or would it need a manifold and exhaust to get that sort of power?
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Red Escort 1.6LX
Then - Red Escort 1.4
Then - Silver Fiesta ST 170BHP
Then - White Fiesta ST MR200+
Now - Mitsubishi Evo IV Forged 2.3 500BHP
and Mondeo Mk3 2.0TDCI