This morning (on a COMPLETLY EMPTY 3 Lane hwy), I was letting my baby run a little and 3rd gear just would not end! Ususally, 3rd tops out around 110. For what ever reason, today I took it to 120 with 250 or RPMs left to readline??!! The car pulled to 120 like it normally pulls to 100...don't know what happened, but I like it! Maybe she's anxious for spring

 

Very interesting maybe it's your tires, are they the same size as stock or are they 45s? If they are smaller than 120 should be normal, although not correct.

 

None of the Sumi HTR+'s have the same revs-per-mile as the MXM4's which will throw off the speedo and odo. The OEM 215/50R17 MXM4's are 819 rpm and some of the HTR+'s are:

215/50 829
225/45 834
235/45 823

Sumi does make an 18" HTR+ that is 820 revs-per-mile, but I'm assuming you have oem rims.

 

Good point on the tires....My Sumi's are the stock size 215/50 on the stock rims. If the stockers are 819 rev/mile, and the Sumi's are 829 revs/mile, does that mean my odo is recording sligthly less than actual miles? This would also make the speedo read slightly higher than accurate as well I suppose.

 

Yes the speedo would read a little higher. but only by 1.2% for the 215/50's so that means that if the speedo reads 75mph you are actually travelling 74.1.

 

http://www.miata.net/garage/tirecalc.html