I decided to contact TWE (TechWorks Engineering Inc.[Tom]) for information on the Equal Length Headers. These are produce for our 08-11 Impreza's and I thought I'd shed some light for those looking for gains and also share my findings for my own future purchase/others. The email goes as followed:
Our headers are true equal length +/- 0.25”, and have 1.625” primaries with a merge collector having a 2.125” venturi opening up to a 2.5” outlet or 2.0” venture opening up to a 2.25” outlet. The latter is preferred. Flanges are laser cut. The header has 2 double slip joints and they do not leak! All fitment points are the same as OEM. We do locate the primary cat to the secondary pipe which does require extending the O2 sensor wires for the second O2 sensor. We utilize a high flow 200cell metal substrate cat for the secondary pipe section. This secondary section is generally built with a 2.25” pipe up to the cat and 2.5” out. All items are 304 US or Canada grade stainless steel. Every component is manufactured in the US or Canada . The pics enclosed are of the prototype and do not show the venturi section now employed in the design.
These Headers are available for purchase! The only downside is the steep price but think of it this way, your paying for top notch quality and since when are car parts cheap
. When I am able to purchase these I will report back hopefully with results, it just won't be for a while due to money issues. [I do not work for TWE or am I associated in anyway with TechWorks Engineering Inc.] Happy New Years!