I dont think anything on a c8z dyno numbers justify its cost. 5g for exhaust for 5hp , 4g for eventuri intake for 5hp .....Tony Mamo is a great guy , ive had his products on an 02 ws6 , c6z06. Had soler tb on my c7z07 nothing but a flat spot and stumbles. Mamo gets my vote all day. If you look at LMR packages they include them in the stg 1 and 2 pkg and say they are worth it. Stg 2 LMR package 760hp ..... each to they own.Interestingly enough I asked Davenport Performance about a throttle body " upgrade " to go with the Corsa Extreme exhaust and cold air intake install and they said they don"t recommend it because their Dyno numbers don"t justify the cost . Which I thought was pretty honest on their part . Have you actually seen testing that showed an increase in HP ? You would think more air , so add more fuel . In this case they suggest not .