We offer our own line of custom chips to maximize your individual modifications and fuel requirements. At the moment we only offer 8-bit upgrades for the 1990-1994 TT and 1990-1992 NAs. We offer chips, bin files and also socketing services. We recommend you ONLY use trusted fuel injectors! "JECs" or "DWs" do not fit the bill. They are merely drilled out, modified, and or Chinese garbage. We can email you the tune file if you have a Nistune board. If you want a file put (file only) in the mod list and choose "will call" to keep from getting charged for shipping. If you need socketing services please send your ECU with Order # receipt to our address listed on the site. Flex Fuel Tune requires Type 2 Nistune Board with the latest feature pack and appropriate flex fuel kit. Please call or e-mail us for more information. FP= Feature Pack from Nistune - call for more information *** This product is for off-road competition use only, not for use on emission controlled vehicles. *** If you are ordering - Please email us a Mod list (additional items that effect air/fuel), transmission type (manual or auto), fuel Octane type, Injector Size (cc) & Type, Intake (single or Dual), Please include your order number with the email.