The strut refers to the type of front suspension which is a macpherson strut design which basically means that strut/shock/spring assembly replaces what would have been a upper control arm and shock assy. This macpherson strut becomes an integral part of the front end. A number of cars have started using this setup due to costs,weight savings, simplicity, the term strut refers to the whole unit, the strut insert is what you used to think of as a shock absorber. These can come as an insert which goes inside the strut assy. or they can come as a complete strut unit , housing and shock all one piece, you can't take this type apart and replace the shock insert you have to replace the whole unit. Many cars are this way, the bmw's have a replaceable insert in them Wikipedia has a somewhat accurate description here of the macpherson strut front end
The rear suspension is also a mcpherson strut type , only its a called a chapman strut, Colin Chapman of lotus fame, mr. cheap and light himself came up with this modification of the macpherson strut for the front and adapted it to the rear suspension of his cars. Technically these are still called inserts on the rears and its still a strut type suspension since its acts as a member of the entire suspension not just as a shock absorber.
These mcpherson and chapman struts were all intended as cheaper lighter more cost effective replacements for the traditional double wishbone suspension that most of your exotics still use such as the corvette and ferrari's.
Originally Posted by Scott H