Do it mate, despite being heavy and big the GTS has always impressed me on track. Even Llandow being a small and twisty circuit it made it round there pretty well and had the smaller stull like Elise's on the straights. Where else can you learn what the car can do properly these days without losing your license or killing someone.
The only other thing to consider is noise levels, you won't want to drive the car out of SPORT mode on track as the traction will really hold you back, if you open the valves you are into 120dB territory and they will black flag you!!!!
Don't get goaded into a race, this is where it all ends in tears, if someone is faster than you then indicate and let them past at the next safest opportunity.