Will LSI-Splits pair up well with KP4000c's?

[buckskin]

I need help, please. I have one pair of La Scala splits, and one pair of KSM-2"s. The KSM's are first generation, I think. They are 32 inches tall, 15 inch woofers, one handle on the top, and a pole receiver on the bottom. Mr. Bob Crites and his son Michael rebuilt the LSI's crossovers last month. (LSI's are new to me) Both sets of speakers sound great to me. All of these have K-43's in them. I use these for two channel listening. I want more bass. A seller has two, KP4000c's. Approximately 10 years old, used about three times, stored in a closet for the rest of the time. He's asking $600.00 for the pair. He also said he had a Rane AC22B crossover he would sell with them. (He said cheap) First of all, are these subs a good match for the speakers I have? If so, how's his price? I currently have a Crown XLS1500 for each KSM2 (1050 watts), and a Crown XLS2500 for each La Scala (1550 watts). With the amps I already have, do I have enough power to run these subs, or will I need another amp? I have two sub outputs I'm not using, that may work. I'm not sure. All of this is a rather new hobby to me, so any good advice is welcome. Thanks.