Anyone else suddenly feel like their GTI is not fast enough... 
Not sure if its just down to the warmer weather but my car feels like it is lacking 
I think you just got use to it!
I feel exactly the same after a few months everytime I trade-up to a faster car.
This is why there is a huge market for the tuning industries for speed junkies like us!
You can easily get bore with straightline speed, this is why I tend to buy car that is fun to drive even at low speed (Steering feel, crisp gearchange and sharp turn-in etc..)