If you have an early car I am sure most owners who actualy use the 3W will have problems. The chassis will break on all the early cars if used. However Morgan fixed mine and others with no quibbles. The original compensators will fail eventualy! They dont even work on the Harley's they were designed for.
However it all depends on the milage you do.
The original 1mm wall thickness silencers will all fail eventualy.
All unvented cam belts will fail prematurely. However the spacer kit does work
Morgan have played fair with me but their coms are woeful.
I ve done all the mods and have now covered 18,000 miles; the last 12,000 without a problem. Well apart from the rear sprocket. But though worn badly is now quiet.
Would i do it again: yes absolutely.