the water hose hook up is a perko flush kit and it works fine. however, some people on hear advocate the bucket method over this kit. I have used this kit on my boats for many years with no problems.
you can determine if you need to wet sand or not by trying rubbing compound first and see if gets the oxidation off enough. ifnot, go with light wet sanding, 3M heavy duty rubbing compound, 3M finesse polish, and then a good wax.
yes that is the blower hose broken. replace it all the way back to the rear. may need to remove fuel tank to route it back there.
you can buy stainless cup holders on line. good places for stuff include skidim.com, rambo marine, jim@baws on this forum, your local dealer, etc.
1993 Blue Stars and Stripes Prostar Powerslot 351HO
Mastercraft: Face It - If you are not a good skier behind this boat, you are not a good skier.