Just done this on my own on axle stands and side jack !! if your confident drilling holes and can turn a spanner its not to bad, but i wouldn't do it again unless i had a helper its a pain to keep getting out from under to check the holes you have drilled and get tools etc.
To give you an idea these things will need doing before you pick up your drill...
You need to remove spare wheel ,under side plastic splash guards, drop the exhaust from the centre back,lower the fuel tank,remove the exhaust heat shields from the centre and disconnect the handbrake adjuster.
Don't mind answering any questions if you get stuckT:
Hi, yes the previous post was right. If you can get the vehicle up in the air its much easier. Remove spare wheel, handbrake cable, drop exhaust, remove belly plastics, heat shields, and drop the fuel tank(try and make sure it is almost empty though!).
You then have access to the chassis rails and you will see predrilled holes in the chassis rail which need to be drilled up or down through the floor.
You will need to install the rails (x4) squarely and parallel to each other as they have a cog system in them which needs to line up with each rail. There are chassis strenthener plates available from vw which we always fit for safety.
We are based in West Oxfordshire and charge £350 for this work + the cost of the brackets which are approx £35. We also issue a fitting certificate at no extra charge.
It sounds complicated but really just a lot of speed nuts and bolts to undo and lots of measuring before drilling.
If you need help just ask.
Colin 07799 626310
We have caravelle seats in stock inc rail systems, flooring etc
consider the variotech seat with it's twin rail. You can have these fitted aswell with rails to your spec'd length and a pretty fine seat. I saw one, think it was on NickBab's build thread. Looked great and simpler than the VW system if you don't already have a caravelle.