I have heard that using............
 

.............an x-pipe along with chambered mufflers(flowmaster) negates the scavenging effect of the x-pipe and thus you should use stright thru mufflers like dynomax with x pipe. Is there any truth to this rumor and does it really even matter on a lightly modified car?

The affect on a slightly modified car is probably not even worth debating. I would say go with the least expensive model (probably, the H-pipe).

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