This article is from the Lotus Cars FAQ, by firstname.lastname@example.org (Alan F. Perry) with numerous contributions by others.
From Ian Peters (email@example.com):
These cars are very reliable if maintaned correctly.
Chassis rust in "rusty" countries.
Chassis fall apart at high mileage if the suspension is not
maintained. (shocks especially)
Handbrake linkages and calipers require constant attention to stay
Rotoflex couplings should be sprint spec.
The alarm switch in the glove box is invariably faulty and
causes tacho failure/intermittant and various ignition maladies.
Later cars with alternators can eat water pumps.
Corrosion in cylinder head if proper coolants not used.
Stub axles break on cars sprinted or raced
Broken rotoflexes can break calipers off or damage rear suspension
5 speed gearboxes painfull/expensive to rebuild.
These cars are seen as less desirable and therefore less valuable
than an Elan. Some of the backyard engineering used to keep these
cars running is ghastly. Inspect very thoroughly before purchase.