20vt.lt - Education

VW MOTORSPORT

https://www.vwracing.co.uk/ - this is massive VW Motorsport video library containing material since 1986

CAR BUILDING AND RESTORATION

http://dutchbuild.com - Hi-end 4motion conversions, SSP's, Haldex controllers, amazing restoration/fabrication skills and even more. A must!
http://www.build-threads.com - A very nice idea to gather all the best builds around the world.
http://www.engineswapdepot.com - Cars, boats and almost any swapped unicorn can be found over there.
https://www.facebook.com/Haidea-1065609513484243 - Audi Golden era (Group B) related B2 builds.
http://www.propontiac.com - Pontiac build from Sweden with high custom-made level.
https://www.facebook.com/Elan-Motorsport-662026323873874 - Elan Motorsport from New Zealand. The masterpiece where E21 BMW has saved only it's look.
http://www.forum-auto.com/marques/ferrari/sujet676.htm - Ferrari Testarossa resurrection.
http://www.914world.com/bbs2/index.php?showtopic=133908%20 - Porsche 914 transformation into track toy.
http://papadakisracing.com/ - Papadakis racing - ultimate car builds for various categories of motorsports.

ENGINES

FORUM BOARDS

http://speedtalk.com/forum/index.php - Engine geek place.
http://www.clubgti.com/forum.php - A must for all of the GTI owners.
http://forums.ross-tech.com - Nice forum for anyone owning genuine Ross-tech VAG-COM interface.

MAGAZINES

http://www.racecar-engineering.com - News, technologies.
https://www.highpowermedia.com/c/31/race-engine-technology - Technology geek edition.
http://www.onallcylinders.com/ - Tips, tricks, articles about engines, etc.
http://www.superstreetonline.com/ - News & reviews.
http://www.dsportmag.com/ - Both online and paper magazine for people who cares about performance.

DOCUMENTATION/LEARNING/REFERENCE

http://vwts.ru - Great source for VAG schemes, documentation and self learning material. The site itself is in russian language.
http://www.volkspage.net/technik/ssp/index1_eng.php - Self Study program (SSP) - VAG - 1 to 100
http://www.volkspage.net/technik/ssp/index2_eng.php - Self Study program (SSP) - VAG - 101 to 200
http://www.volkspage.net/technik/ssp/index3_eng.php - Self Study program (SSP) - VAG - 201 to 300
http://www.volkspage.net/technik/ssp/index4_eng.php - Self Study program (SSP) - VAG - 301 to 400
http://prsearch.planetvag.com/ - VW & Audi PR code decoding tool
https://www.enginebasics.com/ - Engine basics explained
http://www.turbo-product.com - Turbocharger listing by vehicles.
http://www.dieselevante.it/index_it.asp - Turbocharger reference.
http://www.turbo.ee/?lang=eng&id=11 - Turbocharger reference.

ELECTRICS

http://www.loam.org/vw/Vanagon/VanagonProTraining/DigiFant - Digifant I & Digifant II reference.
http://www.not2fast.com/VAG/InjectorCup.html - VAG fuel injector cups.
http://www.clubgti.com/showthread.php?219775-Fusebox-FAQ - VW CE1 & CE2 electric systems reference.
http://www.a2resource.com/index.html - Model guide, color guide, electrical systems, pinouts explained, details of any tranny available for Golf mk2.
http://www.corrado-club.ca/tech/vwecucodes.htm - Plenty of data regarding Bosch ECU part number.
http://s4wiki.com/wiki/Tuning - Useful URL for anyone who wants to tune their Bosch ME7 ECU's.
http://en.wikipedia.org/wiki/DIN_72552 - DIN72552 is standard for automobile electric terminal numbers.

DRIVETRAIN/GEARBOX

ENGINE DESIGN TOOLS