Since I got this car it has had a clunking noises every now and then when I'm accelerating. It never bothered me until I replaced the cat converter. The clunking got worse after that so I went to the mechanic and asked what could be the problem. He showed me that the cat converter was pressed against the underside of the car. So I went home and readjusted it so it's clear from the underside, and though the clunking has lessened, it now is happening when I'm coasting and even in 4wd (clunking used to go away with 4wd. Do you guys know if there's a way to lower the cat converter or how to get rid of the noise?

In my world I would first suspect a failing driveshaft.

I had the same problem with my Brumby/BRAT, the clearance is pretty tight. I found the best way was to (a) trim the cat sleeve, and ( add some washers under the bracket that comes from the gearbox that holds the exhaust system.

Going to step out on a limb here, could part of your problem be your motor mounts or transmission mounts? Maybe both? During acceleration would make me suspect of their condition.

At first I suspected bad motor mounts, but I've had the sounds change on me everytime I readjusted the cat converter. And the sound seems like it's coming from where the front and rear cat meet, where the spring bolts attach. Is it possible that over tightening them can worsen the sound? I feel like the cat has enough clearance to not hit underneath the car when I accelerate hard (unless it can move up around 1/2").