Recommendations re Parts for the Mazda 3 MPS

Hi, I've just joined the forum and looking for some advice.
Bought a late model 2009 MPS Mazda 3 (90,000) about a year ago and after having basic work done (brakes, plugs etc.) it's run really well.
Only issue has been a strange annoying not to loud "clunk" coming from somewhere towards the rear of the vehicle. At the 90,000 service Mazda believe it might be from "rear left sway bar linkage"
Main reason for this post is they have quoted $300 for parts but there seems to be a "whiteline" brand that sells for half that price. Is it better to stick with the dearer parts that Mazda supplies or are there other equally good OEM part suppliers within Australia?

Advice appreciated

$300 sounds steep, did you check if everything under there is tight. You could probably get a whiteline sway bar and kit for around $300. Fuel tank baffle is also known to come loose and clunk around inside the tank.

Thanks - just been serviced and I asked them to try and determine what the "clunk" was and they said maybe the linkage - are "whiteline" parts usually good

Mike