I bought a set to use with my twins that are going on next month and as usual couldn't be patient enough to wait to install them at that time. These things are smokey with the poor little HX-40 I have - it just doesn't provide the airflow and boost necessary to burn the fuel these things deliver. I can be driving down the highway in 4th with the TCC locked at a constant 70 mph and there is a steady stream of smoke. Even at peak boost of 45 psi, there is still a lot of smoke! These observations are without the fueling box on - with it on - can you say total solar eclipse?? I think with about twice the boost - especially at low RPM levels, they should be drivable in polite society - so for the time being - I'm going to put the DD3's back in. Oh, BTW, the increase in power is amazing, if I keep the RPM up I can break the rears loose through 3rd gear at each shift - I just can't tell if I'm leaving people behind incredibly fast or if they're all stopped because they can't see 
