Erik,
700USD is a lot for the CDL kit, but... I paid nearly USD 2,000 to have it installed by a dealer who "did not know" that a kit existed, ordered the parts separately (much more expensive), and took 18 hours to assemble it! (well it was a '04 non-CDL version for Spain).
The cost depends on if your truck has the CDL actuator. If it does, you will need the simple kit (lever, bracket and cable, as illustrated in the images). If your truck does not have the CDL actuator, you will need the complete kit, about $700 in ashcroft.
Nevertheless, the CDL kit fitting is truly recommended. The truck's behaviour is totally transformed, especially in snow (i have two D2, both CDL fitted).
Hope that helps
Regards,
Robert
1992 Santana 88"
1995 RR Classic 300 Tdi
1999 D2 V8 manual g/box
2004 D2 Td5.