1.  The GBBT02565 use the same springs, the spring is a bit more compressed      

In the GBBT02565, which is why the spring rating is one PSI higher.

2.  The supercharger spring is specifically for supercharged cars only,if you

    have a quick spooling turbo it can actually push the valve open briefly before 

    the charge gets To the manifold, dumping boost.

3. GB BOV’s need a 1/4” inner diameter DIRECT source to the manifold,

   smaller lines can cause delays in response time.