I have a panel mount G150 that works great linked to a Apollo for a moving map. I have the hopes to upgrade to a GNS530W. I have looked at several used " yellow tagged " unites. Looks like they are affordable. This will clean up my panel and get all in center stack since I removed a old two head ADF. Is there more than I think to this? I realize the installation is costly and I need the GLS69 to match. What else?