So I Performed the "Washer" Mod - (Flame-suit ON)
 

So I was bored, had $7 to kill and was tired of how quiet my NISMO is. It has test-pipes but with the stock exhaust it's too darn quiet. So I did the washer mod over the weekend.

Sound: Not bad. Really deep (and really loud) with no rasp at all and very little drone. I was shocked at how good it sounded to be honest.

Power: This is the reason I put it back to stock the next day. The car felt EASILY 30-40 HP down. No throttle response and no top-end power AT ALL. If the power would have not been affected (I knew it was going to be, but I still wanted to hear how it sounded) I might have seriously considered keeping it that way for a while.

Anywho, I'm now back to quiet (stockish exhaust) and contemplating my next mod.

Yeah i just disconnected my muffler and exhaust tips. They were still held on my the hangers and there was a 2 inch gap between where the two pipes and the gaskets would meet. Sounded really good but i did feel a huge loss of horsepower.

go get a tune

It's all your head then. I've dynoed with the full exhaust and with the muffler removed as you describe, on the same dyno on the same day and saw absolutely no measurable difference. One was just a fck ton louder.

I removed my muffler to see how it sounds but the smell that comes in, not worth it... Wondering if it's the same with washer mod

Not sure if serious..