i put in a Champion 3 row aluminum, it had a very very small leak straight away. it did drop my temps nicely though. The people at Champion said they would replace the leaky radiator, but suggested I try some stop leak. The stop leak, stopped the leak and also plugged up everything in the cooling system, which brought my temps back up.
Then I had a front brake lock up on the hi-way which caused a bad overheat. The jeep has never been the same since. I put the old stock unit back in.
Champion did stand behind their product, and sent me new radiator, it did take about 4 months. Also the Champion aluminum unit is super fragile. When I was pulling the original champion out, 3 of the 4 aluminum studs that hold the top rubber mounts on broke off. then the radiator barely made contact with the engine driven fan, and that put a hole in the core.
Long story short, stay stock
just my 2 cents