deffo not me lol
as soon as a company wants your engine in exchange, then smell a rat;-)
theres a few places like that , that advertise in the exchange & mart.
i bought an engine once for a bedford rascal van (customers) cost a grand and was told it was fully reconned, after they fitted it bill came to £1400 and after 2 weeks i drove van away and it was still chucking out blue smoke, so they got it straight back again.
these lumps havent been reconditioned, if they have a blown h/g for example, its just repaired and knocked straight back out again!
and theres a clause in the warranty that the company carries out servicing to 5000 miles in a lot of cases (for which you get charged an arm and leg) or warranty dont apply.
but they will always find one way or other of getting out of it anyway.