It only wears the synchro out if you force the transmission into gear. If you're anywhere near the proper RPM the synchros don't have to do a lot of work, and they don't wear out as fast.

 

Skipping gears when upshifting is not recommended. The reason is that the input shaft to the transmission is spinning at engine speed. The synchros have to slow the input shaft down when you shift into a higher gear. If you skip a gear, there is more speed differential between the input shaft and the intermediate shaft in the transmission. The synchros then have to work harder to slow the input shaft down.

Either way, though, you shouldn't have a grinding 5th after 1500mi.

Personally, I never shift into 5th quickly. There is no need.

 

i have 2100 miles on my evo and no grinding anywhere

 

update:

turbo 2.0 is my roomate,

The dealer flew a regional Q.C. service rep from Dallas to look at the car. Mitsu is concerned about it also!