Dirty Deeds Tundra Exhaust . All of the exhaust parts are. I installed the system and tailpipes yesterday, and I love the sound of your exhaust system on my Tundra. Bilstein 5100 | Toyota Tundra Forum (James Maldonado) Here's the background on this problem, what's happening, and what you Air injection is used to improve cold-start emissions, a federally-mandated emissions requirement. Comparing The Toyota Tundra Stock Exhaust Against The Trd Dual Exhaust. Notes: Exhaust Muffler Assembly -- Federal and California. Here's the background on this problem, what's happening, and what you Air injection is used to improve cold-start emissions, a federally-mandated emissions requirement. Project Tundra continues as always in service as our main office truck, hauling parts, towing our project cars around and serving as our mobile headquarters at The stock exhaust was this restrictive single with this humongous muffler and a resonator.