I'm going to change the timing belt, I'll probably get mitsi to do a trans flush as I want it done properly and haven't done one before, don't know how much fluid i'll need etc.

But I'm planning on Tbelt, cam and crank seals, water pump, tbelt tensioner, valve cover gaskets, plugs.... anything I'm missing here?

At a rough guess, it's probably ok to get most bits from an auto parts store but the Tbelt tensionser should be from mitsubishi. Anything else I should go genuine on?

Have done 4G64 belts on nimbuses before and V6 on 300ZX but this is my first Mitsi V6. Car is a TF 3.0.

Also this gets over looked alot is your fuel filter and air filter

While there do a oil change, Coolant and brake fluid change as well

The belts and service items can be purchased from us, we will I am sure save you significantly compared to what you will pay at an auto shop

If you want the trans done properly, do it yourself, grab 15l of fluid, will be more than enough and process is listed in the workshop manual.

Do coolant, plugs, brake fluid and filters, belt, water pump as mentioned and you are about there