Hmmm. Double-checked and the listing in the ITCS line for the EX indicates 15" wheels but 14" for the Si. They both came with 14" stock, right?
The valve sizes are indicated as different too. Perhaps all of the numbers are suspect, since the EX is listed with a 2621.0" wheelbase (218 feet or so)!
I am done with classes in May. Just that little dissertation thing to take car of...
K