Although a good practice is to match brands, it isn't required unless specifically stated by the manufacturer.
A couple of common scenarios that will require a matched brand or at least a matched OE part number:
1. Certain vehicles are equipped with multiple variants of a flywheel from the factory. Sometimes these change which clutch is needed. When searching for OE clutches, if the fitment note states "only with Luk flywheel", then you will need to confirm whether your vehicle was originally equipped with a Luk flywheel.
2. Aftermarket upgraded clutches will sometimes specify a specific flywheel needed. For example, most Spec clutches require a specific Spec flywheel noted in the fitment notes. This is also the case for most cars converting to a single-mass flywheel from a dual-mass flywheel.
If there are no fitment notes related to a specific pairing, then it is safe to use different brands.
To shop for clutch and flywheel kits for your vehicle please enter your vehicle information on fcpeuro.com underneath "Select your Vehicle". Simply enter your Year, Make, Model, Submodel, and applicable trims. Once your car is selected at fcpeuro.com, our catalog is automatically filtered to show parts that fit your specific car.
Once your car is added to the selector, there are a couple of important ways that we advise correct fitment.
The first is the "fitment indicator" shown on the Product Page after selecting a part. This box is below the "add to cart button" and has two states. It will either say " Yes this part fits" or "Part may not fit, click to verify".
Sometimes the green box will be accompanied by extra fitment notes. These notes may be independent of the information gathered by the vehicle selector. IE: VIN-specific options, need to be taken into account when determining overall fitment.