This could just be me, but I CANT STAND THOSE FART-CANS on anything, especially a lexus es

 

That's why you stick to name brand exhausts...not those no name ones you can find at any muffler shop.

 

most everything has been mentioned
but the piping is 2.5 up to the resonator then goes to 2.25 to the muffler so if doing a change remove the piping from the resonator back to a 2.5 inch pipe stainless steel and mandrel bent to reduce the bulges and curves for backpressure issues
the larger an exahust tip the louder the noise or fart
even well know companies have these crappy sounding exhausts
the wider ( or the more its design gets away from being a perfect circle)
an exhaust tip is the more reduction properties it has against resonance
a speaker boxes perfect dimensions should be a ball
fo resonace which inceases sound
i have a 4 1/2 inch wide tip but only 1 1/2 inches higher
a very deep sound ask mcv20
he has a round one
also the wider the muffler the better not just the tip
just a thought to ponder
and besides if you change the piping
you can get rid of that funny bend under the car that looks like yours is broken

later

 

That's actually not true. My Greddy Evolution has a 115mm tip, BUT the actual exhaust opening from the canister is about 2" to 2.5" in diameter. The rest of the piping from the cat is 2.75". It's not how large the tip is, it's mainly on if the exhaust system has resonators...and how well insulated the sound baffling material in the canister works.

 

why am i not surprised
you agree to disagree
all together it is a greater sum of all the parts but the biggest noise influence
is the tip
belive what ever you want

 

You obviously learned much from your "auto" shop class at your community college. You of all people to recommend exhausts? You were bashing an aftermarket company on what parts CAN'T be made for the ES the last time I recall. That's really great advice coming from a gas station mechanic.