Budster:
In keeping an open mind on this, the more I hear you the more I wish I had it....
I went through the same as you Budster but I learnt the hard way though a scare that was avoided by the TPMS, when I ticked the TPMS option on my 997S when I ordered it I didn't realise back then how important it was. Imagine you grab the car in the morning, you parked last night in the garage with no problems, you have to travel to another city 100miles away were you cruise at 160km/h speeds with short burst going over 200 or even ocasionally over 250... as soon as you take the car out of the garage to get on your way, TPMS light pops up notifying of rear left tire underinflated.
You think, I can't be, the car moves fine (you are 500m from the garage by now), you step out of the car to visually inspect the tire and you don't see anything wrong with it, its not flat, and looks the same height as the other tires...you always have that mental image that with a flat you always see the sidewall downland pinched by the wheel, so you think, must be a fault of the TPMS
You get in start driving and again the message pops up. So that "what if" pops in your mind and annoyed you stop on the street again and take out a manual tire gauge that you always carry in the glovebox, and check the tire and to your surprise, there was barely any pressure on the tire!!! I mean, barely any. Why is the sidewall not down visually? then you think, the hard carcass these PS2's have and the low profile of the 19" wheels? I could not believe it. So you start to inspect the tire closely and there it is, a screw logged into the tire. You sigh in relief that you didn't hit the highway that morning with the car, and think what could have happened on a fast long highway left bend, or eventually at the highway exit, or avoiding another vehicle that made a wrong move, or an obstacle, etc... or even if you noticed it eventually through the side wall degradation without having an accident you would have been stranded far away from home without a spare tire, loosing work, etc.
And so you limp it back to the garaje and grab another car and go on safely on your trip that day and come back to your family that night.... well, this is what happened to me one day. The price of the TPMS was worth its weight in gold for me that day. And I have had slow puntures before in cars, noticed them sometimes visually, or sometimes as soon as you drive the car like once on my ex-M3. Not with this 997.
Same with PSM, I learnt a similar lesson about the importance of PSM on street driving on my ex-996 in the rain avoiding another car that jumped into my lane without looking on a bend while I was accelerating out of the bend on a rear engined 911 on the wet.... I'm pretty sure I would not have regained control of the car after avoiding the car without PSM, and given the circumstances it would of been and "ugly" accident, fortunately I regained control without hitting the car or the concrete sidewall of the motorway, its was reduced to just a scare.
That is why I will not buy another car without it. Mind you also that Porsche's TPMS is much better than the one found in other cars I have driven. The one in my Q5 only warns of deflation with a light, thats it, which is the basic safety feature, but no real time readouts of the pressures, nor the delta vs factory pressures independantly of the temperature of the itres, etc. The bad thing about it is that its not retrofitable
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