Additional Options:

For a total of 2 programs (i.e. - Stock and Chipped)	$149
For a total of 3 programs	$219
For a total of 4 programs	$289
Security Lockout	$59
Fault Code Erase/Throttle Body Alignment (FCE/TBA)	$59
Anti-Theft System	$199

APR's S4 Exhaust is a stainless steel, mandrel bent, cat-back exhaust. Our exhaust begins after the two lower factory catalytic converters and is two 2.25" pipes that merge into one 3" pipe. This exhaust is very quiet and simply changes the tone of the exhaust to a deep, unobtrusive sound. With TIG welding, fully stainless construction, and CNC'ed hangers, you will not find a higher quality system on the market.

APR's S4 cat-back exhaust is available with two different sound levels. The Stealth exhaust helps to maintain the S4's subdued character. While louder than stock, it is not too loud to attract attention. The SRT exhaust replaces the center muffler with a special side resonator. This exhaust has a more aggressive sound and a distinctive note.

Package:	Price:
Downpipes with Cats and Testpipes	$1,475.10
Stealth Catback Exhaust	$908.10
SRT Catback Exhaust	$908.10

APR's A6 Cat and Downpipe Exhaust replaces the the exhaust from the turbochargers to behind the lower factory catalytic converters. The system removes the factory pre-cats right off of the turbocharger and includes six separate components. Included are the two pipes off of each turbocharger, a set of pipes with catalytic converters, and a set of test pipes without cats. With TIG welding, fully stainless construction, and CNC'ed hangers, you will not find a higher quality downpipe system on the market.

Package:	Price:
Downpipes with Cats and Testpipes	$1,556.10
Catback with Tips	$1,079.10
Catback without Tips	$1,079.10

Enter the R1: APR's R1 diverter valve addresses all of the reliability problems of the factory-supplied diverter valves and aftermarket replacements and takes performance to the next level. The R1 is a diaphragm-based valve. A diaphragm is the best option for a diverter valve for several reasons. First off, a diaphragm has negligible friction. Piston-based valves have considerable friction from the piston, o-ring, and bore assembly. The lower friction R1 diaphragm equates to faster response and better overall performance. Secondly, diaphragms do not require the periodic greasing that piston-based valves do. Piston-based valves must be qreased periodically (usually every year or sooner), requiring removing the valve from the car, disassembling and reassembling the valve. The APR R1 was designed to be maintenance free for the life of the product. Thirdly, a diaphragm based valve will never have a stuck piston. Piston-based valves periodically incur stuck pistons (especially if the required maintenance schedules are not followed.) Due to the lack of a piston, the APR R1 solves this problem.

The R1 is designed for optimal performance. The main body of the valve is investment cast in an aluminum alloy. By utilizing this casting process in lieu of a more conventional machining process, APR was able to optimize the internal geometry of the valve to provide the ultimate in flow performance. This geometry cannot be created utilizing conventional machining. As such, the APR R1 has much better flow characteristics than other diverter valves. Combined with the low friction diaphragm assembly, this equates to a valve that is truly a performance leader.

The materials used in the R1 are standard setting. The diaphragm is created out of high temperature material and incorporates a Nomex fabric reinforcement layer for enhanced durability and a diaphragm that will never tear. The alloy main body is finish machined at APR and receives a multilayer corrosion resistant and cosmetic enhancing finish. All machining and final assembly takes place at APR headquarters in the United States for optimal quality control and consistency.