Well a little searching around..
This is right off of Shep's site under recommended oil to use;
"There are several gear oils that will work depending on horsepower or intended use. For most transmissions we recommend Redline MT90 or Pennzoil Synchromesh."
This off Jack's site;
"For our DSM transmission rebuilds we recommend factory Mitsubishi 6-speed manual transmission gear oil from the 2005 Mitsubishi EVO MR."
This is off TRE's site;
"I highly recommend REDLINE MT-90 gear oil as it has proven itself a worthy oil for those who are making lots of torque, shift fast, and wanting long service life from their transmission."
This is also of TRE's(Team Rip) site about using the Synromesh\Syncroshift products, kind of makes me wanna swap it out...
"While it has been found that the Synchromesh/Synchroshift type oils can sometimes improve the effectiveness of the synchronizers, allowing for faster shifts at higher rpms, this oil does not have enough film strength to ensure long gear and bearing life for the Mitsubishi transmissions.
Synchromesh/shift type oils are used in transmissions that are found in low torque applications that don't ask much from the oil in regards of film strength. Transmissions that call for Synchromesh type gear oils are designed with wide gear shaft spacing which greatly reduces the force on the gear teeth and large bearings so that they can used these low film strength oils. The reason behind it is to reduce parasitic frictional losses and to improve shift quality.
If you have a weak synchro, you may want to try the “Synchromesh/Synchroshift” type oils. However, it is our strict recommendation that you use the proper GL rating that the transmission was designed to use. Check your owner's manual for this information.
Use of GL-5 spec gear oil is not recommended in your manual transmission. The EP (Extreme Pressure) additives found in GL-5 will reduce the effectiveness of your synchronizers making the transmission shift poorly and tarnish them over time. How quickly will it eat up the synchros? This is dependent on both time and temperature but it's a gradual process. However, it should also be noted that if you are wanting an oil that does provide higher film strength and added protection against gear & bearing wear, you may consider using a GL-5 spec gear oil. Just remember that it will not shift as good at the high rpms and that it will oxidize the synchros over time"
SO... all in all, I think I will be swapping out for Redline MT-90 in the near future..