I have read up alot on these. Everyone somewhat respectable on any forum for almost any other type of car I have seen has said these don't do squat. The only people that really seem to stand behind them have something to gain.
I really don't see why extending the space between the TB and intake manifold would do anything, look at the intake manifold, could this really change anything at all with the airflow? I already have a long smooth intake tube from my injen, does the throttle body ruin my efficiency so badly I need an extra half inch space to give me better milage and more power..... If the air valve in the TB is 100% open, doesn't it allow the air to flow freely?
What exactly is the thoery here? I can understand polishing and porting the intake making the air flow faster to gain power, but adding a 1" $100 + piece of aluminum.... Come on....
I think it'd be easy to claim a small enough increase in performance and gas milage that noone would be able to or bother to prove it wrong. Seems like a performance placebo for those of us that have this sickness. Sorry I'm not that sick, but it's close.
it's funny, I saw these things surface for subarus on ebay for about $100, within a week the vendor that sells them had them for $150 and no more ebay guy seling them for $100. It wouldn't be worth the trouble if they were free IMHO.
A TBS is great at one thing: Lightening your wallet!
These are left over from Carburettor days, where it was POSSIBLE on SOME engines to get more power by helping fuel atomization since the spacer was downstream of the carb jets. Nowadays with fuel injection being right at the cylinder head, a TBS can have no benefit except bling.