The windage tray was not hard to install, Just cut the old factory tray out if you want and stick the new one in place. Test fit it and make sure it clears everything then weld it down in a few spots.
The crank scraper was also pretty easy to install. Just loosen the bolts on the caps on both sides, take off the bolts on the side you put the scraper on and bolt the scraper back down. I put the washers under the scraper to make it fit better and only needed to grind off two spots to make it fit without hitting anywhere.
As far as how much this helped I am not sure. I did this at the same time I shaved the head and went over the car fixing any problems I could find. If I had to guess I would say it might be worth 0.5MPG at higher RPMs. Anything under 2000 I can't see this helping a lot. But I would say for anyone that has to take their oil pan off their metro for any reason it is worth doing since it is a very easy install and pretty cheap.