Ummmmm.... there is no 2020 trailblazer with a 4banger.... you're talking bout the 2.5L Blazer I'm assuming. If so not sure how the engine is setup for the Blazer but probably any generic universal K&N but it's been widely proven with GMs 4cyl turbos to just go with stock airbox and a K&N or AFE Performance air filter for best results because of the crazy engine bay heatsoak. Exhausts are a dime a dozen no true full exhaust will be cheap. Think over 1200 range on low end. 4-500 for just an axle back.