Before I decided on the turbo kit, I purchased and installed a Summit cat-back for my fox. It has the "turbo" mufflers. Are these ok in case I decide to y in the downpipe? I've read about the flows and chambered mufflers being a negative, but wasn't sure how these were classified. They're not "straight-thru" like a bullet, but I think they just have packing of some sort. Thanks.