Hi all

I've reading the site for a couple of years but never really had anything to share until now.

The door lock mechanism in my 2007 RX8 is playing up and in trying to get a new one I've discovered the high price of these things! 250 Swiss Francs / 200 Euro / 172GBP. I managed to dig up the part number and did some online searching and eventually found a company in the UK who basically just distributes OEM parts direct from the dealers for a really good price.

Being a forum and all I feel I need to strongly stress I have no affiliations with any of these companies but just found them useful for saving a buck!

Firstly I'd like to recommend partsbase.org as you can browse by model and get the exact model number for the item you're after. For example after I found the door actuator above I started searching for the coil part number as an example and found them pretty easily:
MAZDA RX-8 2003 [AEFA06] 04.2003 ROTARY-ENGINE SUPPLEMENT: ENGINE ELECTRICAL SYSTEM

Next is the stockist, well, not really a stockist as he doesn't stock anything!
eurekacarparts.com

The drivers door lock actuator unit is part number FE27-58-310E and the site just lists it as a Mazda item and that's it. Barely any description (just "N/UK LOCK R DOO (Mazda)"), no photos, but they can get it for a good price. This is the one I purchased:
FE27-58-310E | N/UK LOCK R DOO (Mazda)

Total including £1.99 delivery to the UK was £90, so from the £172 (probably without VAT or shipping) it's 52% of the original price.

If they have what you want for the right price I thoroughly recommend them!

All the best.