I actually have a 96 talon tsi awd, with a 6 bolt 4g63, so I have a little experience with the Mitsu engine. I say for sure ditch the balance shafts. If done properly, it should improve the overall reliability of the engine. It's not so much a performance mod as it is a reliability thing. The way I understand it, these shafts spin at twice the engine RPM, so I can imagine, lubrication is pretty crucial to these. All the balance shafts do is to mask a vibration that is inherent to the motor by adding a canceling secondary vibration, if that makes any sense. Just an unnecessary part that can fail. Remove it. These engines need all the help they can get in the reliability department. Also, they can handle quite a bit of boost, but I wouldn't recommend that for an endurance race. If you go turbo, stick with small boost.
Also, speaking from experience, on the turbo motor, there is an oil cooler attached to the block that the oil filter fits onto. When removing that filter, it's easy to loosen the oil cooler from the block. I dropped all of my new engine oil out merging onto I-35 that way once. Quite a spectacle. I'm sure no one is as stupid as me, but just some advice from a dumbass: Make sure the nut holding the oil cooler is tight before replacing the oil filter.
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