i wrote a write up last week about me replacing my vss but here's some quick info for you it's not that hard just make sure to let the motor cool overnight your hands will thank you.
Yeah it's not bad to replace if you can get your y-pipe bolts out it depends on how rusted they are, if they do break it's no a big deal just simple hardware nuts and bolts will fix it.
The best thing to do make sure to spray the bolts down with the rust breaker before you start after that just remove the y-pipe bolts.
theres 2 for the front ****** 2 for the back and 2 where the y-pipe meets to the rest of the exhaust they should be 14mm nuts after that remove the heat shield from the vss housing unplug the vss electrical connector and then pull the pill holding the speedo cable in and then remove the 10mm bolt holding the vss sensor in place and remove the sensor swap over the spedoo gear off the old vss and repeat the procedure it took me about 2 hours but it would have taken less if i jacked up the car and let the motor cool over night.