A freeflow exhaust causes a leaner mixture, normally the mechs just screw up the CO with the idle mixture screw, right way would be to install bigger main jets.
That's the theory, effectively you don't need to do anything as long as the car runs well,, they run rich enough when the throttle is open, idle mixture is set to an appropriate level using the emission tester and set lambda ~1.

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RaymondQV
Countach QV Ex-Mimran #GLA12997, Urraco P300 #20530 sold in August 2008, Jalpa #FLA12203 sold in May 2006
www.countach.ch
www.jalpa.ch

When Frank Sinatra got his Miura S in 1970, he said: “If you wanna be someone, buy Ferrari - If you are someone, you own a Lamborghini”.