The biggest risk of the OEM torque converter is the blades coming apart and exploding internally. The more common risk is the clutch piston cracking and giving a lockup shudder condition. When I had my 3 clutch billet converter rebuilt, I asked them to send me photos of the as found internals. It was all like new after 13 years.
As for the tugger kit, I'm not a huge fan of shift kits. Shock loading the drivetrain and transmission internals isn't such a good idea compared to the risk of wearing out clutches a little sooner. Hard parts are expensive to replace. Soft parts are not. So if you do add a shift kit, I would keep it pretty mild. If you need more torque capacity, I recommend adding more clutches, not higher line pressure.
Your truck is turbocharged, so I wouldn't skimp too much on upgrading the hard parts. I highly recommend the later pump and make sure you have the steel carrier overdrive planetary. Power enters first through the overdrive geartrain, no matter what gear you are in. I upgraded all my gears to steel carrier (overdrive, forward and reverse), although forward and reverse carrier failures are less common.
Being a 1994 model year, your transmission should already have the ball-bearing center support. If for some reason it doesn't, I highly recommend upgrading it.
A single, good quality cooler is more than enough for most applications. Mine runs around 100F unless I'm slow crawling up a mountain road...then it gets up to 180 in some cases due to lack of airflow. If ramming uphill through snow, I've seen over 200F (my temp sensor is on the hot side cooler line). This is why some recommend not bypassing the factory cooler, and I'm starting to agree.
The converter is the biggest source of heat, by far. So if you're towing in 3rd or 4th with the converter clutch applied, there won't be much heat generated by the transmission, no matter how much load you put on the truck. If you have to gear down to 2nd on a mountain pass with a big trailer, then the transmission becomes a massive heat generator, and this is where you need the extra cooling capacity.
I also agree that a bigger pan is not worth the money. These things already have a huge oil capacity. I also like the idea of a stamped sheet metal pan vs aluminum, because it won't crack as easily if you bottom out on something. If you need more cooling, add a bigger cooler up front. If you want insane amounts of cooling, install a factory cooler from a 6.0L diesel and upgrade the cooling lines to 3/8". Use steel lines, not rubber.
All that being said, what's wrong with it right now? Is it starting to fail?
