Carbon wheels set or new groupset? Currently, I'm running on Claris 3x8 speed drivetrain. I'm planning to either upgrade the groupset or a carbon wheelset. 

I dislike the groupset because of it's heavy and loud but usable but I want more gears in the rear.

I'm leaning towards carbon wheelset because it could save major weight and its more aerodynamic.

Any thoughts?
You should evaluate your objectives.  What advantage do you feel a new wheel-set or groupset would provide?  If your objective is to ride faster, then I would suggest you invest the time in building your aerobic base and physical strength with interval training and some resistive weight training.   If your objective is to look cool then do what you wish but it is unlikely that
 1. a stock carbon aero wheelset exists for an 8spd hub
 2. it would be cost effective to have a set of wheels built with your existing hubs.

Also,  your stopping power will be compromised in wet weather if your bike has rim brakes.

A bike is not like a car where an upgraded component can improve performance. You are the engine and there are minimal gains to be had with components perceived to be better. A pro cyclist or strong amateur can outperform most on a $100 big box store bike.