Honestly, the car is a very stable platform through its life. You will not make a wrong choice with either. Its all about how much you want to spend now as its a weekend toy. Take it easy and enjoy your car , which ever you pick.
Buy this one - then you don't need to spend thousands making your purchase better:
That option aside, it's hard for anyone but you to know if you want to spend an extra £5000 or not. Is there anything wrong with a GT86 on 50k mileage? No, not at all. Accident damage is easy to spot, and the clutch is unlikely to be worn and even it it was, it's not as though you wouldn't have the money to replace it.
Be sensible, spend less.
Or avoid all risk, and spend more.
Either way, try not to over-think it and just go!
