I have had trouble with Bosch spark plug wires in the past.

I installed new Bosch wires and experienced a plug wire go bad with less
than 3K miles on the set.

I searched for an alternative plug wire set made specifically
for the 2.1 WBX engine.  I found what I was looking for in
Magnecor Spark Plug Wires.

http://www.magnecor.com/magnecor1/main.htm

The #4521 8.5mm plug wire set for the 2.1 Vanagon is $60.00 from
Alamo Motorsports.  This includes the coil wire and four threaded
caps for the spark plugs.  They are correct length with good fitment.  I am
very pleased with this wire set.

http://www.alamomotorsports.com/Magnecor/mag_volkswagen.html

JB 88 GL Guido