I've heard that the m3 has hiccups in throttle travel and is smokey, and has some issues. Is this because its too middle of the road? cant decide between the m2, 3, or 4.

 

Never heard of issues with "Throttle Travel" with any AFC fuel-pin. They're not connected. The AFC is boost pressure driven.

Sounds like poor tuning.

That being said, those fuel-pins with very sharp drops in the ramp perhaps may be having problems moving back and forth in it's bore (with the AFC needle binding against it).

I've run the fuel-pin products from both Denny-T and M&H. I currently run what might be called a M&H 2.5 (custom). It sports a ramp VERY much like the OEM fuel-pin's ramp (flat).

I recommend the M3 as it has a more linear ramp (more flat ?). That allows better excess smoke control as the fuel comes on at a more uniform rate, similar to the boost pressure.
The others have, at one point or another, a fast dropping portion of the ramp that brings the fuel on too quickly. Often before the turbo(s) have spooled to meet the demand (excess smoke).

 

my apologies, i meant more of the fuel delivery would studder, or pulse. like you would stomp on the go pedal and it would surge. thank you for your imput and advice. i will order an M3 very soon.