I know there have been recent posts regarding this - both from a vendor that admitted after dyno tests that the addition of their product would result in slightly lower power in the low rpm's, & members that have dynoed their cars after certain exhaust modifications that also saw a loss...
Don't really want to mention again who these vendors are, but apparently the possibility exists.
And I use the word 'backpressure' loosely - not near enough space to go into gas flow theory (and no one would read it anyway)
Whether or not this loss can actually be felt?
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