Recommended a highly resolving cartridge

Hi all, all tube system that is warm with a good midrange presence inherently. I’m looking for a cartridge that offers high detail / resolution and wide / deep soundstage. This is on a stock SL-1200G TT. On a side note, if anyone has experience “upgrading” the stock tonearm on a G please chime in. I’ve read conflicting reports of the merits of such a move, and while I’m very happy with the tone of my TT and am not looking to move off of it, I am curious about a tonearm swap (must allow for headshell swapping).