Adding a remote will not be a problem, cost depends on what series your
L4400 is.
Single spool remote for an
L4400 is $802.00 plus installation
Single spool remote for the newer verison
L4400-1 is $753.00 plus installation.
The remotes for the older verison
L4400's were not the stackable type, so if you thought down the road you might need a second valve you would want to purchase the double spool valve initially.