Concor Superliners--replacement trucks?

Hello, folks. Newbie here with a question. Sometime before the last ice age ended my father recieved as a gift a set of Concor Amtrak Superliner cars. He’s very fond of 'em, even in the face of the newer Walthers offerings, and recently got a Kato F40 to tow 'em around. He will probably drop interiors into them. But what do people here think about replacing the trucks–has anyone done this, and can suggest or warn about the various alternatives?

Thanks in advance for your thoughts.

Train Station Products makes some great replacement trucks. As you see, they are kits but are easy to assemble with some plastic cement.

http://www.walthers.com/exec/productinfo/732-411
http://www.walthers.com/exec/productinfo/732-410