My current setup is all stock piping with just the muffler cutoff at the back.

The sound is not bad but bit of a drone up to 2000rpm and little buzzy at the highway.

The stock muffler is way too quiet though, also saw on 355nation someone who cut open the stock muffler and was pretty restrictive as well.

So leaving all as is, just want to put a Flowmaster muffler.

I originally wanted a super 40 since it seem like the most popular one, but the noise level concerns me as their website has it labeled as an aggressive sound.

The other choice would be the super 50 but don't know why it's double the price of the 40 series.

Suggestions?

 

I really don't think that a super 40 will be that much louder than what you have NOW. I did the same as you (cut off the muffler at the rear). You tube has some H3's with different mufflers.

I have friends with the 50 series and they do not like them. They sound good, just not loud enough.

 

I think that's what I want. More free flowing than stock without increase in sound levels.