lightroom plug ins

[LCPete]

Hi if you use a lightroom plug in such as perfect effects 8 to to work with to do things like set the black and white points with auto contrast or change the colour balance is it working on the original raw file like lightroom does before you convert to a tiff or do plug ins work on the file after its been converted using whatever white balance you have selected
Sorry if I've not explained myself very well I've just been trying perfect effects and it's great and am wondering if I can use it for doing the raw conversion in light room instead without loosing any of the information in the raw file
Do I need to get the white balance ect roughly right in lightroom first before using the plug in or can I go straight to perfect effects
I don't really understand how these things work but love working on the raws in lightroom you can do so much and perfect effects looks like a great addition to that

Edit I've found out that lightroom exports the file to the plug in then you work on the tiff in the plug in not the raw