40 PSI front and rear up to 3 passengers.
Yes, 40 PSI. I had to read it twice in the manual.
Tyre_pressures_for_Vauxhall_vectra_SRI_120_CDTI_1.9_tyre_are_215_50_F17_91W
215/65R16 tires have 26 psi cold
Yes it can.
Tires are rated for different pressures. Look on the tire at its min and max pressure ratings and make sure your in the middle. It is written on the sidewall of the tires.
0.8 inches.
I tried to fit the chains for a 215/70R15 on a 215/60R15, and the chains were too large. I suspect in your case the chains will be too small.
this means the with in centimetres
It usually can
40 psi
If they have the identical aspect ratio and wheel diameter as comparing a 215/70-15 to a 205/70-15 the 215 tire will be .56" taller.
235/60-15 or 215/65-15 are both acceptable swaps. I would go with the 215/65 as you may have clearance issues with the 235 series tire.
Unlikely, it's MUCH wider.