Originally Posted by pyroman131

Let me spare you the disappointment first: throttle body spacers offer no benefit to vehicle performance.

The general consensus around ScionLife (and other car enthusiast forums) is that when paired with other drivetrain modifications (e.g., cold-air intake), a TB spacer can aid in performance... potentially. They're commonly a placebo modification - you feel like it's actually doing something because it changes the characteristics of your driving. Do you accelerate faster? Nope. But you think you do simply because you invested the time and money in the installation. They're supposed to "direct" more air into the engine making it work less hard, but none of this is proven on Scions. Think of it like the cheesy air intakes you see on eBay that have propeller-like fans designed to "direct" air.

If you really want to attack the throttle body area, look into porting and polishing.

Further, if you're looking into increasing HP as cost-effective as possible, using an intake, header, and exhaust is your best method for maximizing air flow through the engine. You can typically achieve on average 10-15 horsepower with bolt-ons. If you want true speed, your only option is forced induction. Beyond this will become expensive as you'll have to replace the actual drivetrain (e.g., Scion tCs featuring a shoehorned V6).