[Gav]

A torque converter is designed to allow a certain amount of slip, that design is based on the weight of the car, engine size, cam specs, anticipated use, etc etc
Any engine has a minimum rpm where it begins to make power efficiently, so a torque converter will be designed to allow the engine to slip or flare up to this minimum rpm, thus allowing it to immediately operate in its power range.
So...a converter designed for a commodore will be 'tighter' than one designed for a 1100kg cobra because its a heavier car needing more torque to get it moving. Using that converter in your cobra will result in it being quite sluggish off the line (if an LSA could be called sluggish) fitting an aftermarket converter will just allow it to operate as it should.
A hi stall is a term for a looser converter, a big cam makes power at a higher rev range so a high stall allows the engine to flare up to a point where the engine is starting to make its best power.
Now to dispense a common misconception, a small high stall like 2800rpm won't make your car undrivable, driving around normally you won't pick it's there, once you mash the throttle it will allow the engine to flash up and away it will go, but it will be very predictable and not at all dangerous.
Trust me, you will be VERY glad you fitted one.