Balky shifting on '98 540 6-speed

[beachcomber_bill]

My 540 is getting a bit hard to shift, especially when cold. I have replaced the shifter with an M5 unit, which improved the feel of the lever but did little to ease the pressure needed to get from one gear to another. A guy I know has a 99, and the difference is huge; his just glides right into each gear. I was wondering if a fluid replacement is in order. If so, any recommendations? Also, should I be concerned about the transmission mount, or the bushings that hold the shifter "bridge" to the transmission? Any feedback would be appreciated. By the way, it has about 152,000 miles.

Thanks!