Can't buy the G550-based system, since the G550's out of production. Italy bought a few just before it went out of production, IIRC. to retrofit, but AFAIK no manufacturer is offering it as the platform for an AEW system now.
South Korea is buying the same (but I think updated) Israeli radar to that on the CAEW G550s operated by Israel, Singapore & Italy, but on Bombardier Global 6500s, integrated by L3Harris. The chief competitor was the SAAB Globaleye - also on Global 6500.
SAAB is offering Globaleye to NATO, & for a possible Nordic joint AEW fleet, & it's been selected by France. I think L3Harris may now be touting the system it's just sold to South Korea to NATO.