Throttle body spacer.

[circmand]

How it works, supposedly:
http://www.carsdirect.com/aftermarke...e-body-spacers

Whether they work or not is debatable. There's a lot of info out there on the web....check it out. For the price of it....mmmmmm....I'm going to have to pass until someone gets it on a dyno.

I'd be more interested in intake manifold spacers.

There is always a ton of info on the web. But 99% of it is crap made up by people who want to sell it to you. On the Interweb you can create fake web pages and fake experts and pretty much fake anything you want. Thats why people need to understand the need for real sources like newspapers instead of reading what some 30 year old guy living in his parents basement writes.

[bartmanS4]

It's my understanding that these provide a trade off that gives you better performance at higher RPMs but not quite as good at lower RPMs. This is also what is shown in their dyno graph inset with the benefit coming in around 5300 RPM. Since I rarely go over 4k RPM in my VX this would likely have a slightly detrimental effect on performance for me. Think of a turbo lag but not quite that noticeable. If you spend a lot of your time in the upper RPM ranges you'd probably see some benefit.

[circmand]

It's my understanding that these provide a trade off that gives you better performance at higher RPMs but not quite as good at lower RPMs. This is also what is shown in their dyno graph inset with the benefit coming in around 5300 RPM. Since I rarely go over 4k RPM in my VX this would likely have a slightly detrimental effect on performance for me. Think of a turbo lag but not quite that noticeable. If you spend a lot of your time in the upper RPM ranges you'd probably see some benefit.

I even understood what you said.

[eternal21]

There is always a ton of info on the web. But 99% of it is crap made up by people who want to sell it to you. On the Interweb you can create fake web pages and fake experts and pretty much fake anything you want. Thats why people need to understand the need for real sources like newspapers instead of reading what some 30 year old guy living in his parents basement writes.

I'm not going to disagree with you. When I research stuff, I usually look at reviews. However, having a little knowledge of these from past experiences.....these were big when older cars used TBI, or throttle body injection, when fuel sprayed into the throttle body. Doesn't do much for other fuel injected systems.
The reviews of them:
http://www.silveradosierra.com/engin...ers-t4921.html
http://www.ford-trucks.com/forums/36...dy-spacer.html

Intake manifold spacers, however...those reduce the temp of the air going into the combustion chamber. As such, these work. There are plenty of independent reviews out there as well as independent dynos to back up the claims.