Do I need to change the front axle because I keep hearing people say I need to
If the splines are different then yes. But I would try to slide your axles in the new trans before you go buy new axles. These trans get swapped around a good bit. Might be one that's same spline as yours.
What's wrong with your trans?
Looking for a Used 3000GT in your area?
CarGurus has 80 nationwide 3000GT listings starting at $2,999.
Search Mitsubishi 3000GT Questions
Mitsubishi 3000GT Experts