i installed new rubber on the rear yesterday...255/40/19 PS2 and the front remains the 235/35/19 i originally had. to make it short, the cluster lit up like christmas tree...slip, vdc off, abs light all lit up. is this due to the width and aspect ratio of the tires i used? advice and opinoins welcome. TIA.

 

I'd say that's the most likely cause. You're running tire sizes that are over 6% difference in circumference ( per this : http://www.miata.net/garage/tirecalc.html ) which exceeds the tolerance built into the car's systems.