SL55/63/65/R230 AMG: cats
From reading on the forum there is 4 total, 2-primary and 2-secondary.
Do I need to replace all 4 or how can i tell which ones are bad?
Better to replace just the primary's and straight pipe the secondary's? will that throw a code? )i will be getting a tune/pulley soon once i find the best place)
Heard Venom cats are good? Any suggestions? Size?
Thank you!


