Changing the tranny fluid is easier than the engine oil. We are talking the 6MT, right? Did mine a couple weeks ago and the hardest parts were getting the car off the ground (car needs to be reasonably level) and then hand pumping in the new fluid in. You just fill it up until drips out of the fill hole.
BTW OP I just put Red Line MT-85 in my trans (ordered 4 qts to be safe and only used 3.25qts). No complaints on the fluid so far. I didn't notice a huge difference from the stock Nissan fluid as there is still an occasional notch in 1 and 2 when cold or when trying to shift fast. You may also want to check out the diff fluid as the initial diff drain was nasty.