Neuspeed also has a shortshifter..I had it in both of my S4s.
The same B5 platform is found as far back as 1996 in the US (2.8 V6 cars only) and 1995 for european cars.
The transmission issue is most likely the first/second slider gear getting jammed. I think this is a better explanation that just the synchros. I was there when Don Istook replaced his on his S4 race car during a race weekend at Laguna Seca back in 2000/2001. I know numerous people that had issues with this.
Thanks for the write up.

Steve S
**RIP O.W.Kenobi**
current cars:
07 BMW 335i Sedan - Morr Alloy VS7 forged wheels/Goodyear F1-D3/Bilstein PSS9 coilovers/Ultimate Racing catback/Alcon 4pot 365mm brake kit
90 Mazda Miata - commuter car
previous Audis (in reverse order):
05 A4 1.8TQM - Dolphin Gray
01 S4 - Laser Red
99 A4 1.8TQM - Aluminum Silver
00 A4 1.8TQM - Volcano Black
01 S4 Avant - Laser Red
83 4000E - Beige Metallic
00 S4 - Nogaro Blue
97 A4 2.8QM - Laser Red