i looked it for my 1999 Pontiac transport.....i got this from best buy website
Radio
Radio fit: DIN
Kit needed: Yes
Front Speakers
Front Doors: 6-1/2"
Speaker bracket needed: Yes
Speaker harness available: No
Rear Speakers
Tailgate or Rear Pillar: 6-1/2"
Speaker bracket needed: Yes
Speaker harness available: No
Add-on Amplifiers
Audio cables needed: Yes
Power kit needed: Yes
The proper tire size for a 1998 Pontiac Transport is P205/70R15. This info is on a sticker placed on the driver's door jam.
The gas tank for a 1998 Pontiac Transport has a capacity of approximately 20 gallons. This allows for a decent range between refueling, depending on driving conditions and fuel efficiency.
A 1998 Pontiac Transport with the 3.4L engine typically requires a thermostat with a 195°F temperature rating. The thermostat's diameter is generally 1.75 inches. Always check your vehicle's manual or a trusted parts supplier to confirm specifications for your specific model.
6x9
34mm
6 x 9
6.5"
Front Speaker Size- 4"x6" and Rear Speaker Size- 6"x9"
215/70-15
i believe stock size is 205 75 15
22 and 17
Listed in your owner's manual and on the driver's door post.