The main issue i have had with TRS is how tight the bolts are on them. The air box does get a lot of mud in it i noticed this especially on my 2016 and the pilot jet in the carb would block a lot. On the 2018 they haven't improved this. You need to make sure you have a really good air filter oil and you grease the outer ring of it. You nearly need to clean the air filter every ride especially in the wet you will even need to take the airbox off and clean it out. From what i gather people grease the seal around the lid and and put tape over it. It helps a bit but the majority of the mud comes in through the rectangular breather in the airbox. I'm still waiting under warranty for my new trs to get bigger orings, as they cut the groves on the cylinder head to deep, so it is leaking coolant which i have to top up after every ride. The chain tension is terrible my bike hasn't even done a couple of weeks worth of riding and its as shaky as anything.