Is it worth getting an S-AFC if you only have....
 

...downpipe & presilencer, full exhaust, and intake?

This is for a 90 GTU.

Thanx

I wasnt aware there were downpipes available for GTU's

I guess you mean header and no I wouldn't think so

Yes, they make a downpipe for N/A's. It runs off the manifold and replaces the preconverters.

And no, you should not need an safc for you mods. Really the only time it's used on an NA is if you're running a ported motor.

You can always lean it up to a safe point, there should be a gain of couple of HP's

turbotwista & fingers
 

http://www.racingbeat.com/FRmazda2.htm

Look for catalytic converter Replacement Pipe (downpipe) with Presilencer.

Hope that clears it up:)

So S-AFC wouldn't be worth it huh? Thanx

You may gain a few HP by leaning it up a bit (they run kinda rich by default..), and you may gain a few MPG... Maybe guess a 1 or 2 mpg increase, see how much that saves you, and see how long that would take to account for your SAFC... My bet, is it would take a LONG time..;)