I am starting to get the itch to upgrade my entry-level road bike. However, I am also cheap, so this is causing some cognitive dissonance

I have a 2010 Specialized Dolce (purchased new in 2011) with a carbon fork, Tiagra derailleur, and Sora shifters. I've never exactly felt like the bike is holding me back, but it is entry-level and a bit old so I am beginning to wonder if I've outgrown it. This is the first season where I'm starting to feel almost like I'm a little bit fast, and I keep wondering how much faster I could be, as I watch people pass me on nicer bikes.

I wouldn't spend a crazy amount of money on a bike -- I think 2K is about my upper limit -- so it's not like I'll go full carbon or anything. I want a durable bike, anyway. Really I'd prefer to buy a used one on Craigslist because new, nice things stress me out!

The husband is trying to push me instead to upgrading my groupset on the current bike. I don't really get why that would make the bike faster, though? I don't have any shifting complaints currently.

OR maybe I should save my money and just work more on the engine