The 91 and the 88 are weight ratings.
The H is a speed rating
Your car needs to be equipped with tires of adequate weight rating and all four the same.
So yes it does matter
BUTMight not in your case, you need to check before changing.88 is the max weight for the tyre, h refers to the max speed allowed for the tyre, in this case 139 mph.
4k-91h
Michelin 195/65R15 91H MXV4+
Loads cargo on trains planes trucks and ships.
Ft. Bragg, Ft. Eustis, Ft. Story,Germany and I believe Korea as well
The most common tyre size is 185/55 R15 88H.
Why don't u try Bridgestone?
Your 2000 Infiniti I30 came OE with P215/55R16 91H Now, you can use your size information to do some shopping...tiretyre.com
91 is The maximum weight of each wheel (in this case means 615 kg = 1355,84 lbs)h is the maximum speed (in this case 210 km/h = 130 mph)
88, 91, ... is regarding max. weight load (88 aprox. 570kg, 91 aprox. 620kg ; higher is better) ; H , V and T are regarding to max. speed - V is about 230km/h ; H is about 200KM/h; T is about 190km/h, and so on.
The tyre is 195/65/r15 91h and the same for the spare tyre but some cars have different tyres due to the fact they have different alloy wheels. Just go on the Kwik Fit or Nationaltyres website and go on tyres and type in your registration number.
matter is definitely matter because matter is the same thing as matter so it is combined and formed to a bigger matter..... (my guess)