As a past Tech for TAD Motorsports (builders of Mitsu Evo rally cars) here in IL, I can assure you that installing a boost controller is a good thing! I installed many, mostly the HKS EVCs and they work great. One of the advantages even without increasing boost levels is the fact that a good controller like the EVC will learn the boost curve of the vehicle and thus boost response is greatly increased. Do not go with an Manual Boost Controller, like CloneGTS said they can get you into a lot of trouble real quick! Example - I just need another tenth to beat that Supra, I'll just turn up the boost a little more..........kablaaaaaaaaaam!!!!!!!