S204 and STi Type RA-R
 

In 2006 STi decided that with the facelift that the Impreza got they would treat us with not one but two special editions. The first special edition was the S204 which is the ultimate street driving hawkeye STi with carbon fiber seats and special suspension tweaks all over the chassis to make it a great well rounded car. The second special edition was the Spec C RA-R which was the complete opposite of the S204 as it was designed to lay down laps at the track and hillclimb events sacrificing comfort for sheer speed.
 

Starting with the engine both cars are almost identical as both have the EJ207 and VF42 turbocharger. Both have the same basic accessory setup with an oil cooler , hard silicone inlet and more power than your standard STi. Worth noting is that the S204 stock rom is targeting around 20psi or around 1.4 bar of boost in stock form which is really high when compared to other models of STi.
 

The suspension , chassis and brakes are where things start to get very different when you compare the S204 and RA-R. The S204 is over 200 pounds heavier than the RA-R due to still having standard glass , sound deadening and creature comforts whereas the RA-R removes all that using light weight glass and even had the option to come without air conditioning. Both cars Both get improved suspension from KYB , STi chassis braces , stainless brake lines and even more little goodies like pillow ball lateral links. The brakes are where the two are drastically different , Both have the same Brembo rear brakes as the standard STi but only the RA-R gets six piston Brembo brakes up front to help it stop faster on the track. Both however do come with STi sport pads from the factory.
 

The interior and exterior also received special touches from STi as well. The S204 got a carbon fiber front lip , STi supplied rear wing and 18x8.5 BBS wheels wrapped in a 235/40/18 Pirelli P Zero tire. The RA-R got 18x8.5 Enkei wheels wrapped in a special 235/40/18 Bridgestone Potenza RE070 tires. The interior of the S204 was wrapped in a dark suede with carbon fiber recaro racing seats replacing the standard STi seats. The interior of the RA-R is identical to a Spec C in stock form because STi assumed that you would replace most of the interior with aftermarket parts or parts from your local STi dealer. The special thing about the RA-R is that if you were one of the lucky few to order the car you could have optioned it out however you pleased with things such as STi Recaro racing seats , bigger sway bars or upgraded clutches straight from the dealer.