Not sure which gearbox route to go down in MK2 ABF...

You're a star, thanks very much!
I learned something new today!

A year (or more) ago I noticed in ETKA the 084311313 part number for the sync keys. I wasn't sure what was different, so I bought 9 of them or something, they arrived and I never noticed the longer flat section. I put them on the shelf and forgot about them.
When you mentioned the key part number, I thought it looked familiar and I checked my parts bins, where I found a bag of them I had purchased from VW.

I also recently got an order in from Shanghai of 3rd/4th sync hubs and sleeves, assembled. I had to fight the factory because I specifically asked if their hubs had the rounded key slots to prevent cracking and they sent me the old style, with the square cuts. They finally agreed to send me the correct hubs. I checked the old parts they sent, and sure enough, they are using the new longer keys, so I have the proper sleeves to match the longer keys already!

The short key 014311313 has a flat spot about 5mm long, the new 084311313 keys have a 7.5mm flat spot.

So... thanks to you and your info, I will now start fitting every rebuild with the new hub style with the rounded key slots (something I've done for years), but I'll ALSO start using the new style sleeves and the newer keys with the longer flat spots.

Next will be to mock up an input shaft with everything assembled, and see what it feels like to over-shift 3rd, to check to see if the keys pop out.
I'll modify my Rebuild page as well as the Stuck In 3rd Gear? page, to show the new information and to give credit to Martin aka hotgolf in the UK for giving me the learnin', so cheers for that, I'm quite excited to learn about this AND to already have the parts in stock.

I'm glad I just recently received the Shanghai 3rd/4th hub assemblies, as I've not tried to use one yet... I would have fit it with the factory VW keys and springs I always have, which would have been the wrong parts for that new style sleeve so you saved me screwing up in the future by fitting the wrong parts together AND you taught me about the new keys and sleeves.

Fackin' brilliant, nice one!

Brian

*edit* -- As a token of my appreciation, the next time you need 020/K reverse idler gears, let me know. I'll supply you some for less money than anywhere else... cryo treated, great quality idlers. They're small enough I can fit several into a Flat Rate box to keep postage costs down.