The mx5 seats are a bit crap, however I’ve used mine with a mk2 CG Lock since day one and that does rectify pretty much every complaint you could have with them. I’ve got a sparco sprint seat in the garage I keep threatening to install, but I love heated seats that little bit too much!
Def get yourself an alignment, as it does transform the car as they’re very sensitive. I remember driving one when they first came out and hated it as it felt so numb, however mine with the fast road geo from Wheels In Motion is pinpoint sharp.