got mine FCP going for 3rd year with less than 20k miles.
drive great, dampening seem to be awesome when now I run no swaybar. recently found out FCP is also consider "extended". No leakage on strut as I am moderate offroad/overlanding.
Rear struts been on the entire time with 2" lift and one spring 1" spacer.
Front is at 2.5" and has been warranty replaced twice. 1st when passenger coil ring not locked and IM think need to be replaced. 2nd is when driver strut rub against the spring (maybe bent strut).
I like the cost effectiveness of IM FCP. so even with those replacements I still love it. FCP struts drives so nice on my heavy rig at 6500+ weight.
I think it is also serviceable at 30k miles or so.