New S3 8V owner - some questions

[Gruffalo]

Hi. First time S3 8V owner here.
Loving the car but have a couple of questions hopefully someone here can help.
1- something was rattling around in the boot well, I found the offending item, a metal washer but I also found this. Does anyone know what it is? It doesn't look like a valet key, is it even related to the car?

2 - When I took delivery the car had 2x Michelin ps4S on the front and rear passenger side and 2x hankook s1 evo 3 on the front and rear of the drivers side. All 4 tyres had same tread depth so I swapped the ps4s onto the front axle and Hankooks onto the rear axle. After this the car gave me a TPMS warning for the rear left. I checked all pressures and re stored them in the system but did this happen because I swapped the wheels round?
Kind regards

 

[leonwilliams]

Hi yeah tyre pressure linked to each wheel in position on car if you change position it will alert you

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[Matt Titanium]

2. Possibly if they had different pressures or rolling circumferences. The car "works out" if there is a pressure change by using the ABS signals and how the wheels are responding.

 

[Damo S]

Personally I would put the PS4s on the rear as I think they'll offer better grip in the wet compared to the hankooks. The PS4s are very good in the wet at the expense of faster wear and quite a bit of road noise. You don't really want the poorer tyres on the rear when it comes to damp / wet corners unless you like your car being a bit tail happy.

 

[Gruffalo]

Personally I would put the PS4s on the rear as I think they'll offer better grip in the wet compared to the hankooks. The PS4s are very good in the wet at the expense of faster wear and quite a bit of road noise. You don't really want the poorer tyres on the rear when it comes to damp / wet corners unless you like your car being a bit tail happy.

My reasoning was that the fronts do most of the work and therefore the slightly better tyres should be on the front, the car would probably understeer on the limit in the wet so makes sense to have PS4S on the front.
Both the Michelin Pilot sport 4S and the Hankook S1 Evo 3 are rated A for wet grip so it shouldn't be that noticeable anyway.
There will be nothing but MPS4S going on the car going forward so it's only a temporary situation.

 

[Mick3]

The thing in the picture looks like one of the long plastic holding pegs that keeps the rear bumper on to the car, it's behind the rear light clusters iirc

 

[Gruffalo]

The thing in the picture looks like one of the long plastic holding pegs that keeps the rear bumper on to the car, it's behind the rear light clusters iirc

That would make sense considering where I found it but I'll have to have a look and see if it needs to go back