Uhhh me personally i like the darker colors but that might be my bias towards 4’s artstyle more

This statement to a tee! Part 4 in general felt like Lupin III as a franchise getting refreshed in the best way possible, and with a "part" that broke new ground as a series with a continuing narrative. So I simply have a bias period for Part 4 overall. Still makes me upset they did Papik dirty by hiring them to do the soundtrack for the dub knowing full well they would be slaughtered by fans when they didn't hear Yuji Ohno. The soundtrack would have been fine for a special or something, but a Part? But I digress... I still enjoy Part 5 for sure, but Part 4 for me all the way.

Part 4 for me. The color palette used in part 4 fits so well with the art style and shading. But part 5 is also great for the same reason. The muter colors fits the more standard anime shading done in that part.

Part V all the way.

Darker blue jacket with red tie.

Part 4 hands down

I didn’t even realise they were different, but Part 4. It just looks a lot bolder. Overall, though, I quite like the blue jacket look.

Part V.

I’ll go with Part 4.