Unless there is someone in the business here you will not get any kind of even a ball park estimate. To get an estimate someone will need to inspect it and have an idea of what you want to replace them with.
There must be dozens of shops in Orange County that do this type of work. I just Googled and found all sorts of shops.
Chuck D.
โAdventure is just bad planning.โ - Roald Amundsen
2013 Jayco X20E Hybrid
2016 Chevy Silverado Crew Cab Z71 LTZ2
2008 GMC Sierra SLE1 Crew Cab Z71 (traded)