Boyesen dual stage reeds

[Grampy]

Here I go again, I don't see Gas Gas listed on the v-force web site. Which one do I use?
Thanks!

[cvl05]

Just a clairification, my 05 de250 has the Boysen reed cage and a spacer, what is the purpose of that spacer?? I was thinking of switching to the v-force for a boost in low end power, i've sent the head off for squish mods and am ordering a gnarly pipe to replace the fatty. Any idea on the use of the spacer?