Lot's of water changes, I'd add a HOB too. I'm not familar with the XP2 but it doesn't sound big enough for a full grown O in a 60g. Personally I like to over filter, with O's it's a requirement.
get him a 75 gallon. but you're better off with tankmates. oscars are messy eaters. get some type of pleco or a couple of smaller cichlids (convicts, firemouths, even a female Jack Dempsey or Green Terror would be good). these smaller fish would help eat the food that will inevitably fall from the Oscar's mouth and gills.
That will be fine for an adult O for life, but probably won't be able to have any tankmates, though you could try. I assume 41cm is the width? If 41cm is the height and 55cm is the width that is much better for the oscar.
ye 55cm is the width and the heigth is 41cm and i really i don't want to get a bigger tank becuase of the weigth , i will have to do some research with fish tanks upstairs on wooden floors.
I had a 120gal on a 2nd floor with no problems in 2 different houses. The weight of a 55 (66) isn't that much if you put it against the wall and across several joists.