Hiya
I thought i would stick my 'tuppence worth' in
I think the karcher are good as long as you have a high end one
poss with a metal pump
As for the Nilfisk it has a metal pump,(had one for 5-6yrs )no problem so far
and as for the foam lance I changed the brass fitting on the lance with a alto on
(bought from Polished bliss Cheers Rich!!) a bit of ptfe thread tape and 'bobs your uncle'
Stu