ok...if your going to go it do it yourself! If your goign to do it yourself you NEED a compresor and an underseal gun (no really you do!)

armed with this and about a gallon of 'waxoil' or similar (clear wax and adatives mixture thinned with white spirit) let it down to approx 50-60% with white spirits and attch probe to the end of gun (tube with omni directional spray on the end) remove ALL rubber bungs from the sills etc and shove probe into sills/box sections bits where you cant otherwise reach an d retract praying as you go.....fit spray nozzle to gun and go the same on any sheet metal joins vissable under the vehicle...remove door lock striker platres etc to givve access to inside or a,b,c and d pillars and do the same - pull internal door cars and do the same...

leave for 48 hours to dry, repeat..

now load gun with Shultz or similar (black bitchumen based preparation)and spray a continuos coat over the unserside of the vehicle...mask first so any overspray doesnbt end up onteh paint...if it DOES you can wipe off with white spirit (polish paintwork afterwards!)

repeat a day later.

now apply a coat of prayed waxoil over hte suspension componants (though obviously NOT the wheels/brakes - mask these FIRST...

your done probably 15-20 hours of work and 2-3 gallons of assorted stuff + white spirit - really messy and fairly unpleasent but anything else is a waste of time!