Yes body body body, SteveFMk1 is completely right.
Rust is the killer on them, far more than the head gasket failure.
MGTF and MGF values have been low for years but that is starting to change. Low mileage models in good nick are really starting to go up in value dramatically. At the moment you can still get some bargains but you have to look harder than 3-4 years ago.
Take a mat + torch and get on the floor. Look around the wheel arches and sills for rust and on the subframe mounts (front a rear).
I am in a similar position myself. My belt is four years old and has done 3.5k. I am on the fence but probs just need to bite the bullet and find time to change it.
I also wonder about many newer cars which have much longer intervals - often 10 years or a 100k for the cambelt change. Maybe In some cases they are different belts but on many engines the interval was extended to coincide with the new model of car despite the belt part number remaining the same....
At the end of the day it is your decision. Chances are it will probably be ok if you leave it longer, but if it does go the consequence s are high. You are likely looking at a new engine or a right off. Your call if it is worth the risk.
Such a shame. Cambelt failure is car cancer, can happen any time to any car.
Unfortunately seems to be happening at lower and lower mileages nowadays on cars that are supposed to be much higher quality than our little TF's. However good the plastics feel and however posh the the satnav they all have the same Achilles heels under neath.
I don't drive my TF much so always disconnect the battery. Not had an issue yet, even when left for months.
However you would have to lock the car manually and the alarm would not work.
I'd be more worried about brakes sticking on. I leave them off but that's in a locked, flat garage with tyres in tyre savers. Would be irresponsible outside - there are stories of cars rolling away when kids nick the brick from under the wheels.
The TF 115 doesn't have the door tweeters or the rear speakers in the T bar as standard like the 135 or 160.
Adding the tweeters and rear speakers is a cheap improvement for a lot less than decent aftermarket speakers. This also raises the sound stage for a much clearer and brighter sound.
Obviously aftermarket speakers are ultimately better, but the standard speakers are not that bad with a decent head unit.