The original neck on the Forum 5 has a great feel. You should try it out. The neck pocket is a Peavey original so you will likely need to do some routing to make a graphite replacement neck fit. Could be a great combination - like a Tim the Toolman version of the GV.
The stock VHL pickups are very good. They are similar to pickups on Cirri, but are wider and pickup from more of the strings. The pickup are also truely huge. They are not only very wide, but also very deep. If Fred ever makes the 5 string Dark Star pickups this is probably the only bass where they will be a drop in fit with no routing needed. The stock 2 band preamp is also good.
If your Forum 5 only weighs 10 pounds then you have a rare light one. The four that I have all weigh in at 11 pounds. All the metal (bridge, tuners, THICK control plate, knobs, etc) and the huge pickups contributes to the weight.
Thanks for the info. If you have that many they must be pretty good. Gonna try it today.