HD, panhar and Steering bars with ball-joints still holding on fine after 9 months and 20000 miles. I've bent the steering bar a couple of times though alright but that was just driving like a prick and with offset 33x12.5s, I can't really blame them for bending. Think the pan-hard bushes are starting to fail now though
Filters have lasted fine each time upto 5000 miles
Silicone hoses seem fine with around 20K on them now too
Wheel bearings are lasting around 5-10K but again, I don't really expect too much of them with the wheels I'm running and regularly dunking them in water up over the axles. The bearing kits are very cheap anyway so don't really mind changing them as they are relatively quick to do as well.
De-cat pipes on my 110 and Dads Disco are still letting smoke through it and hasn't broken off
Passenger side mirror that I can still see stuff behind me with after 6 months and hasn't fell off
Although, the position of the arm is crap as it's that bit slightly further forward compared to the OE one so it kinda gets half hidden by the A-pillar and wind-deflector
Think that's about it on stuff I've tried on the 110 really.
I've fitted stuff from Terrafirma that was a terrible fit when I haven't really had anything from britpart that needed messing with before it fitted
I've used alot of stuff fro birtpart in building my trayback though as it only means a day cut short if something does fail and it just makes the whole build far cheaper even when using everything new.
If the majority of stuff lasts on that, I don't think I will really be able to complain about their quality.