The effect has been dramatic... Before I replaced these parts the engine was really clattery, and there was a deep throbbing coming from the air filter box. Awful, and the car sounded sick, although still actually drove really well. Now it's a different car, lovely and quiet, no more throbbing and runs like a Swiss watch.... Pricey though, followers are approx £12 each, and followers are £16... You'll need 20 of each...
. You'll also need a new gasket, 5 injector seals and the obligatory oil and filter change. Hopefully I'll see an improvement in fuel consumption (or my good lady is going to be a bit miffed!)