I'm running the Stillen right now, I personally think it's s-hit. I lost so much so end prior to my spacer install. I think the stock box is the best option for retaining low end. I'm going back to stock as soon as possible.

And yes, there is a hole on the bottom of the "heat shield".

Tony just installedthe 3/8 plenum spacer for me at the meet today. I wasn't expecting a big power gain from the spacer since I was told around 5-7hp. Well, I didn't bother with the ECU reset and went on my marry way. Surprisingly the power increase is very noticeable at least to me. The engine definitely pulls harder even at lower rpms. I could feel the difference even in normal driving at 3000-4000rpm. The additional power feels like how my coupe behaves on a very cold day with dense air - except it was fairly warm today inland so I know it's the spacer. The plenum spacer is not like CAI or Z-Tube, it works very well and gives you the best bang for the $$$ power increase IMO. Highly recommended.

Damn, I just found out Hydrazine (ie Tony) is a rocket scientist....... somehow I was fortunate enough to have a rocket scientist designed and actually installed a mod for my car - I feel honored. That in itself is probably more worthwhile than the 8-10hp I think I got today.

do you know what hydrazine is

Tony installed my 1/2" spacer at the meet as well. I have header and exhaust mods on my car. The spacer has made my car feel like a slingshot when the tach passes through 4000 RPMs. The car is very quick and satisfying now and the spacer has added this sweet "jet" like sound to the car. I did an ECU reset using the pedal method when I got home. I don't know if that has made a difference, but the car does feel somewhat smoother. This is butt dyno only, but there is plenty of dynos plots out there proving the gains from the spacer.

I also got my engine cover to fit over plenum with the 1/2 spacer. All I did was remove the gromets and rubber washers from the top holes of the cover then reinserted the metal gromets back from the bottom of the cover and then inserted the rubber washers over the gromets from the top of the cover. I then screwed the cover back on to the plenum. I have to push down on the hood slightly to get to lock.

Looks like a foil flexible duct...something like this

Damn Nutty,

I just plotted your dyno data. You had some very serious gains. WTF!?! Either you were packing a mini NOS shot in there or the 1/2" Plenum Spacer works really good with your setup. Damn...

Check this out!

And these.
.

And these...
.

thanks. yeah, great gains. =) i can definitely felt the difference. cant wait for the next dyno day to test oiut the 3/4 inch spacer and the different combos. =)

Do you have to have a TS ECU to fix AF ratio? Doesn't the adaptive ECU learn the mods and add fuel accordingly to enrich the AF ratio?

Wow. Those are impressive gains. No wonder my car feels like a slingshot with the 1/2" spacer that Tony installed yesterday. I'm definitely going to sign up for the next dyno day just to see how my G stacks up to the other cars with the spacer installed.

Has anyone posted Dyno results on the difference in gains between a 6MT with a 3/8" spacer and one running a 1/2" one? I grabbed the 3/8" one thinking it was better for the coupe.

I'm curious if similar gains can be seen on 05s. Or if the current 3/8" spacer will fit on the 05s at all.