Let's not kid ourselves, getting a sub $100 popular handlebar is "customizing"? How about this, if you really wanna make it yours, save your here-and-there "sub $100" upgrades and custom paint the bike.
You wanna buy it because you wanna buy it, that's all.
Anyway, I was thinking about getting a new handlebar, one where the top tube is flat
Sounds like he's wanting to upgrade for a more specific reason than "just buying."
What' YOUR idea of customizing, then. Spending more than anyone else for stuff nobody else has? Customizing and getting popular/plain items are not related.
OP wants to buy and is asking for opinions on what might be good. If you take offense to that then well...