I'm planning to change the timing belt on my 02 KJ Verada shortly. Looking at the workshop manual, it states that you should use a special tool to get the tensioner correctly set up.

Is this necessary - and if so, can you buy them anywhere other than at a Mitsubishi dealer?

havent ever needed a tensioner tool for the belt
its only on a spring

cam removal tool used to fit the new seals behind the cam

http://www.aussiemagna.com//forums/showthread.php?t=52754

Yes, for 3rd gens you need the tool or some way to apply toque to the tensioner.
I made up a wooden tool (took me one hour). but the tool broke. The reason it broke was the small torque wrench i had bought operates in clockwise direction only. One only has to apply a small torque and the wooden tool would have worked if the torque wrench worked in anticlockwise direction. I put too much torque on the wooden too (not realising at first that it does not work in anticlockswise direction) and broke it. I used 2 nails (in the holes) and a piece of metal between them, with a body building 5 kg weight hanging off that by a piece of sting. IF you understand moments of force you can work out how far the weight should be positioned on the metal away form the centre of the tensioner to give the required torque. From memory it was 170 mm (but you work it out). Before using the weight I checked that it really was 5 kg by balancing it on a piece of wood with 5 kg of water on the other end. Coke bottle weighted 70 mg, so I put 430 ml of water in the bottle. This worked for me, you decide if you want to do the same...no guarantees.

If you decide to go the wooden tool method, make sure you have torque wrench that goes to low torque and works in anti-clock direction. Remove tensioner from car (or use new tensioner as your guide) as this will make it easy for you to fabricate the tool....it does not have to be quite like the one shown in the manual.

HOPE THIS HELPS