when I researched about plenums and the mrev2, it shows there is a sharper drop off in peak hp as it approaches redline...i was curious if any gains that occur with other NA mods (i.e. exhaust, headers,etc) would produce similar results. I'm assuming the increases occur earlier in the powerband and don't really effect the redline hp or don't really cause power to drop off before redline like the plenum. Please help. Thanks

 

with MREV you'll get a drop off of 1-2 hp near redline, on the revup motor. With an exhaust, you can make up the difference and then some. Header tend to increase midrange and leave top end with only slightly more HP, around 5-15 (depending on headers and the rest of your intake/exhaust).

 

Some of the dynos here and on the MD website may be for cars with headers. The powerband is shifted somewhat, with a significant gain in the upper midrange (~15) and tiny loss at the top end (~2). I had headers for a short time, and all I noticed was better power near the redline and a louder exhaust note.