I currently have an aluminium frame bike, with Tiagra group set. Bike cost €1000 so wheels are basic.
I am looking to upgrade either the frame, to carbon and keep all the original components, or the wheels.
Which would be better to upgrade to? About a €500-600 carbon frame or wheels that cost around €400? I am looking to select the one which will give overall higher speeds.

Thanks for the help!

Edit: I am a member of a club, and I am able to keep up. I am going to race next year but can't afford a whole new bike, or full groupset. The only upgrade I could afford would be a low end carbon frame or mid level wheels.

Join a local club and try to keep up with the fast riders.

I'd go with wheels. I love how a good set of wheels has low flex, good rolling hubs and spins up faster. Wheels.

darraghm, Choice of cassette is the best bang for the buck modification, followed by a good wheel set. An inexpensive carbon frame set maybe no better than what you have now.

Brad

I would upgrade the wheels. Nicer wheels makes a huge difference, IME. Plus, if you get a new, nicer, bike later - odds are that the wheels you buy will still be nicer than what comes stock on that bike and you can switch them out. Upgrading to a carbon frame with Tiagra components just invites, later, feeling like you might want to upgrade to 105/ultegra. In the long term, independently upgrading frames/components is the most expensive way to go in the long term. However, if buzz from my aluminum frame were there and bothering me, and my only near term option for relieving that were to replace the frame with a carbon one, I'd consider that.

Good wheels are generally considered the best upgrade.