I just picked up an White Bros E2 on ebay for my 426 and of course it came with no instructions whatsoever. I figured out the installation but it came with three inserts and I'm wondering what the db level is for them. One is wide open w/o a spark arrestor which I assume is way loud though I haven't tried it. The other two both have spark arrestors. One has a 22mm diameter outlet and the other has a 33mm outlet. Anyone know???