Improvement in spark plug technology does allow for some styles of plugs to function properly for 100,000 miles. Check with your mechanic to verify the correct spark plugs and expected mileage before requiring replacement.
Tire pressures are normally listed on the tire label found inside the driver’s door on most vehicles or the owner’s manual. Tire and auto manufacturers also have suggested tire pressures available on-line.
Radial tires installed on an original bias-ply tire vehicle will not hurt its suspension. The handling and ride characteristics of the vehicle may be changed depending on the quality of the replacement radial tires.