Alright I am thoroughly confused on what fits my car. Especially in the exhaust department. I'm trying to decide if I want to just do axel back since this is my daily or go full cat back. But what are my options to begin with? I'm seeing things that say anything for a 350 awd fits, I'm seeing other things that say anything for an RC awd fits, and vice versa. I prefer a deep tone with as little pingy metallic sound as possible.

As far as other parts go, are there any "rules of thumb" where if it fits model X it will fit my 2017 IS300 AWD?

 

Axle back - any that fit RC will fit IS and vice versa (regardless of RWD or AWD), the only thing to be mindful of is the diffuser depending if you go single or dual tips

Mid-pipe - differs between RC and IS AND it differs between RWD and AWD even within the 3IS

Hope this helps