Is a high end stem an upgrade that i will notice (Enve, Zipp, maybe S-works). The weight savings are minimal and easy to quantify. Will there be a noticeable change in the ride?
I currently have the S-works Aerofly 2 on a Tarmac sl6 and moved a middle of the road stem from another bike (alloy, mid level Felt).
By itself the upgrade would be from stiffness. I tend to think spending on stems as part of an overall weight reduction effort (stem, handlebars, pedals, bottle cages, bar tape, tires, tubes, etc). If your equipment is lower end you can save a lot of weight relatively inexpensively from going even to midrange. I have a spreadsheet with component weight and then look at upgrades I make on a $/gram basis if weight is what Iām after.