Jason Oppenheim says he's more excited about the upcoming "Selling Sunset" season than ever before ... because a couple OGs are back in the fold.

We got the "Selling Sunset" boss in West Hollywood and our photog asked him about Christine Quinn and Heather Rae El Moussa returning for Season 10.

Christine left the franchise in 2022 after Season 5 ... and Jason says she was one of the reasons why the show blew up.

Jason tells us this season will be packed with drama and sexy real estate listings ... including one property with a nearly $100 Million price tag!!!

We also asked Jason if he'd had any luck locating his $500,000 Rolls Royce that got stolen in broad daylight from his parking lot at work ... and he told us why he doesn't think it will ever surface, at least not on this continent.

Check out the clip ... Jason even talks Chrishell Stause!!!