How about 40 2.8 Leica M ports with Leica m6 switching lenses? Ask to recommend about 3000 M-port lenses with high cost performance?

M6 does not have 40 boundaries, so the composition of 40 heads will be a bit inaccurate. However, the quality of Sonnar40 of Lulai is still good, and so is Summicron-C 40/2 used by Leica CL (in fact, there is Minolta M-Rokkor 40/2 of the same model). In contrast, Leica's 40 is sharper but Jiao Wai is not good, Zeiss's 40 is slightly sharper but Jiao Wai is more beautiful.

Fu Lunda's 35/ 1.4MC is multi-film, SC is single-film, multi-film is more modern, and single-film pursues classical taste. But in fact, almost the entire product line in Fu Lunda is imitating the softness of the lens in the 1950s and 1960s. Personally, I don't hate this imitation (Heliar 75/ 1.8 is the most comfortable one, if you don't mind buying a medium coke), but I don't like Fu Lunda's workmanship very much.

It's more difficult to buy an M-head for 3000 yuan, and you can also consider Konica's Hexanon for 50 yuan cheaper. Or, if you can spend more money, consider Zeiss plan 50/2 ZM or Biogon 35/2 ZM.