why do you say that?

 

because ive installed 3 with no success. they all malfunctioned in one way or another.

 

I have a 4lb lower on my L and I have NGK BR7's gapped at .036. I planned on having a 4lb and a 6lb lower to switch out, but I never got the 6lb and the tune. My truck has ran perfect, so I would say they work for a 4 or 6 lower.

 

BRAKES!!! and the Suspension.

So many people underrate the need for brakes. The L brakes suck after one good stop from 100+mph which the truck achieves very quickly and often. with close to 400rwhp the truck really does need better stopping. Get a set of cross drilled discs front to rear, get stainless steel lines, some autocross/light racing spec pads and you should be ready to go. That is the cheaper route...you could go with a full big brake upgrade with bigger calibers etc...but that is going to be very close to the 2k mark.
Then you can do a quality lowering kit, and lowered spec shocks (for ex. Hotchkins tuned Bilsteins).

After this, you should be able embarrass a few sports cars even on a twisty mountain road, and pass them dead on the straightaway!

 

Can you expand on this?

 

go to rpmoutlet.com they have a nice dyno proven package its the E kit gives you 135 hp and 144lb ft for 1100