Wait a second. Rather than replacing a perfectly good IOTA DLS-55 with another one which has the IQ4 module, why not just buy the IQ4 module itself? The IQ4 just plugs into the exiting DLS-55.
$20 vs $200 - I know what I would do.
http://www.amazon.com/IOTA-Engineeri.../dp/B0030G7ZHM