Cambelt on these isn't too bad a job though its a good idea to replace the waterpump and pulleys too as they have a habit of going too! You can get kits from a few places, i used a Gates kit when doing mine last year. Also a good idea to replace the alternator drive belt too as you have to remove it to get the timing belt off. You'll need a timing kit or camlocks to get the job done, i used the timing kit from ebay, did the job and saves taking the cam covers off to lock the cams.
Brakes could be a sticky caliper but the 156's don't have the greatest of brakes out there!
Knocking from the suspension could be the ARB drop links or bushes or the bottom arms, again not huge jobs but there will be a lot of rusty bolts to deal with!! Top arms tend to squeak when they wear out.
Gear knob on mine is a bit knacked too but after reading a few of the tales on here i think i leave it for a while, lol!! Its glued on and a bugger to get off...
Oil dripping from the cooler is a another common fault, you can get hoses but there are kits out there to replace the whole lot with better hoses and cooler.
Give your map sensor a good clean too, i took mine out and the thing was thick in gunge! makes a difference when clean.
The mutltijet is a good engine and i have a '05 plate and it pulls like a train, though i have fitted a cone filter, decat pipe and a solid lower turbo hose.
The 16v should have 140hp.
I have used ebay, shop4parts, autolusso and rockauto.com for sourcing parts, just be careful as there are some dodgy stuff out there. Also look up the eper website as this breaks down the car and lists all the part numbers which is great for google and sourcing parts!
Hope that helps and good luck with the car