265 Halfcage or harness bar

Hello,

Currently looking to convert my Megane 3 RS interior to clubsport spec as there is never more than 2 people in my car and I could use some better seats at the track. Since most seats come without reclining backs the rear seats become kinda useless anyway, so I might as well convert it to clubsport/trackday spec.

I've been looking into this and I'm currently looking at either a bolt-in half cage or a harness-bar+ eventually a K-brace.

From what i've understand a halfcage doesn't really do that much to both stiffness and safety as they can't be bolted down to something sturdy. If that's the case, wouldn't it be easier/cheaper to just use a harness-bar?

My car will be a daily/trackday car, so no full-blown trackcar or competition-use car.

Can someone give me some pointers to what to chose here?

Thanks in advance.