Q: What are some differences between B5 platform Audi S4 build dates?
A: Audi seems to roll out updates gradually on their cars, so no list may be totally accurate. For example, you may have a M-box with the older shifter stalk. Also note that S4s were released in Europe before North America.09/99 (Y2000 initial production, A-box ECU for manual, f-hose, possibly aluminium uprights on suspension, original badge)
06/00 (Y2001, H-box ECU for manual, ESP controller, possibly steel uprights)
10/00 (Y2001.5, M-box ECU for manual, revised turbos, no f-hose, revised TBB, different oil inlet lines, possibly changed shifter stalk, polished aluminum mirrors w/ sport package, new badge, Avant model)
06/01 (Y2002, T-box ECU for manual)

Tiptronics have a different lettering sequence for their ECUs.

Q: How do I tell what ECU box I have?
A: The best way to be sure about which box you have is to either hook up a VAG tool and see what number it returns. For example, a reading of 551M would mean M-box (for both methods).

Q: What does my VIN mean?
A: Meanings by digit: 1) W = Germany, 2) A = Audi, 3) U = Passenger Car, 4) Series: R, 5) Engine D, 6) Restraint System, 7&8) Model Number (8D = A4/S4), 9) Check Digit, 10) Model Year (Y = 2000, 1 = 2001, 2 = 2002), 11) Assembly Plant, 12-17) Serial Number

Q: Which aftermarket ECU chip is the best?
A: This question is the start of many a flamewar.

Q: What does WOT stand for?
A: Wide Open Throttle

Q: What’s the part number for the BMW M3 spoiler?
A: 51-71-7-893-671.

Q: What are some useful datablocks to log with VAG-COM?
A: Torque (120), Boost (115), Air Flow (003).

Q: How do you calculate HP from Torque?
A: 1.0 NM = 0.74 FT/LBS. HP = (TORQUE X RPM) / 5252.

Q: How many quarts of oil does a S4 hold?
A: About 6.5 to 7.5.

Q: What other Audi vehicles utilize the 2.7 Liter 30 Valve V6 Turbo engine?
A: You can find variations on the engine used in the S4 in the Audi (B5) RS4 (w/ K04 turbos stock), (C5) A6 2.7T, and Allroad 2.7T.

Q: What engine will be in the B6 platform future S4?
A: 4.2L V8 at around 340hp.

Q: How many Audi S4 2.7L Biturbos were imported into the United States? (Production total for USA)
A: From S-cars.org: