I am unclear if you can use both MREV2 and Plenum or if its best to use one or the other to acieve best results on a no-rev engine.

 

unless you plan on getting a tune, then i advise choosing one or the other.

i would pick the spacer because the gains are very similar between mrev2 and the spacer, but the spacer is much cheaper. maybe a couple ponies difference. but it's said that mrev2 alone will give a lil bit more, but not much more.