Spec:
Muffler Style: silent Hi-Power
Style: HP(TYPE-S Oval shape silencer for noise reduction type)
Material: S3 SUS304 High quality stainless
Tip O.D.: 120
Pipe Size: 75
Consist of: 2
Close Sound Level Stock/HKS: 84/92
Idling Sound Level Stock/HKS: 66/70
Remarks: *For applied model E, F. *Fits to stock rear under skirt. *Not tested for "STi SPEC-C", "SPEC-C WR-Limited 2004".
Check HKS page for details

For GDB applied E-F, MY 2005 - 2006

Features:
High quality sound. Sport exhaust system with reduced noise level.
Silent Hi-Power mufflers offer high performance and sporty appearance with the added benefit of reduced noise levels making it the best choice for more mature enthusiasts. Silent Hi-Power mufflers are constructed entirely of SUS304 grade stainless steel for high lustre, long lasting performance. For certain applications, HKS has introduced the "Silent Chamber" which removes a lot of the lower frequency noise that can often be heard into the cabin even when cruising. The silent chamber removes this uncomfortable noise but due to its closed end design, only a minimal amount of exhaust gas flows into it, meaning that the disruption to exhaust gas flow through the entire system is minimized and there is no harm to performance.