For those who have a 23 type-s with the cat-less downpipe, are you getting any check engine lights? I'm looking to go with Function Werks Sport madditive downpipe and the only drawback is that Ktuner is not available to tune.

 

Use a defouler until Ktuner becomes available. Over time you may get a check engine light but it can be erased with a scan tool.

 

I have IMR primary and secondary downpipes with the defouler and haven’t had any CELs since install. You should be good. Good luck.