yeah, they usually get tight when you install them, but as salad said, a couple whacks with a bfh helps.
i use a punch and strike the ears so they open up slightly after i put the clips in, this will make the joint move smoothly again.

always grease up the caps with lots of grease before you put them in, especially with the non greaseable joints cause the factory grease is really only there to prevent rust.
when i use a greaseable joint, i will pack the caps and leave the zerk out until it's together, then install the zerk and grease it up more with the gun.

 

I would use Spicer 760X non-greaseable at the wheels and Spicer 1310X non-greaseable for the driveshaft.

They last a long, long time.

My 01 XJ had one with a seal problem and it was making rust around 250,000 miles. The other 6 u-joints are still original now with 324,000.

To change the u-joints I would spray penetrant on the caps and around the c-clips then hammer them out with a socket. Re-assemble with a ball joint press to avoid jarring forces that may cause needle bearings to drop. If you have a big shop press that would work too, but I don't. I found it very easy to rebuild my front driveshaft this way. You can control how much you press in the cap without hoping to hammer it right and then have to go backwards.