TRUSTY Big Volume Powervalve Cover
 

works and worth the money or just a cool cover?

I havent got the Trusty one but i do have one similar milled out of billet and i would say that it is worth it, as it gives more power down low, makes it easier to lug up hills, mellows the power a touch?

And on the plus side it does look alittle bit trick!

No need to get the Trusty one. Go fasters here in the states has one available which does the same thing.

A must on 200's, good on 250's and probably not needed on a 300

The Trusty unit with the adjuster is high dollar, it's no simple cover. It actually allows PV speed control and/or non-op adjustments.

Speed control. From what I read it could mean actual opening speed, but maybe it relates to when it opens?