Yes its not a difficult task, the biggest issue is getting under the front it helps if the car is lifted then its much easier.
But many have done it with the car just sitting on the road, The second person is there to hold the weight and keep it in place .
Looks aside the advantage the Reiger splitter has is the holes are pre drilled makes it much easier to fit.
Side skirts are just screwed on to the underside of the car with self tappers from memory although they did come with Bolts.
And just to add my car has been round several tracks at speed and had no issues.
Check out
https://www.maxtondesign.co.uk/fitting-manuals for fitting instructions and there are some you tube vids as well for the Maxton one but other guys on here have done the Reiger with no issues as well.