Our Stage 1 Power Package is an entry-level upgrade package for your STI.   The Gruppe-S Power Package #1 is designed to be the best "power for the dollar" upgrade for a completely stock STI.  

As with all turbo cars the large performance gains are found by opening up the factory exhaust system and eliminating the excessive back-pressure.  The Gruppe-S PP1 removes the restrictive factory header, downpipe, and exhaust system and replaces these components with high-flow units. 

The factory header is swapped up in favor of the Gruppe-S V2 Header.  The heavy factory unit is a cast header, designed more for cost then for performance (the JDM STI uses a tubular header).  The runner diameters are increased, and collected into an investment cast 4-1 collector.  Despite rumors to the contrary, we have demonstrated conclusively on the larger displacing STI 2.5 with proper tuning there is NO low end power loss with Gruppe-S V2 4-1 headers. The next component to be replaced is the restrictive twin factory catalystic converters.  We replace these units with the cat-less Helix downpipe which expands the downpipe diameter to 76mm, yielding substantial power gains.*Finally the restrictive multi-chambered exhaust system is replaced with a 76mm (3.0") free-flow unit.  The end result is a substantial power increase as well as an increase in turbo spool up and response. 

*Legal for Off-Road or race use only.  We have a 200cell Metal Substrate version downpipe available.

POWER PACKAGE 1 INCLUDES:

Gruppe-S V2 4-1 Headers - The Gruppe-S V2 manifold is a mandrel bent tubular manifold with an 4-1 investment cast collector.  Significant gains in mid-range and top end are achieved with no low-end loss.       Features       - SS304 Mandrel Bend runners       - Investment cast 4-1 collector       - TIG welded

Helix V3 Bellmouth Downpipe - The Helix Bellmouth downpipe is designed to work with the stock IHI VF39 turbocharger.  Features a cast bell-mouth collector, this downpipe makes substantial power and eliminates the boost-creep issues found with non-bellmouth downpipes.       Features       - SS304 Stainless Steel with TIG welding       - 76mm Mandrel Bent Tubing       - Investment Cast Bell-Mouth design       - Provision for external wastegate        - Wideband 02 sensor
Helix Cat-Back Exhaust - The Helix Cat-Back Exhaust system features a high-performance single chamber cannister with a 115mm tip.  It is a true 76mm design with central resonator, silencer, and is good for substantial power gains.       Features       - SS304 76mm Mandrel bent tube, TIG welded       - 115mm Muffler body       - Includes central resonator and silencer