Had the pleasure today of driving cars that had Xidas and MCA Reds, now it was only a few happy laps of Lakeside but:
MCA Reds
They felt great was very surprised at how smooth the ride was, nowhere near as 'brutal' as mine. Not sure on the spring rates either but it acted very predictable and the ride was firm but not spongy. However, it was not my car so did not 'push' too hard and its setup was more towards daily than track. If you wanted a track/daily coilover would seriously consider these, very impressed!
Xidas
Also got to have my first drive of a turbo car, last turbo sports thing I had was a Kawasaki GPZ750 turbo... Xidas it was not the same ride as the MCA Reds, a little more on the 'harsh' side but still comfortable and again not as harsh as my setup. The car was also predictable in corners and not much perceptible roll, weight transfer was also like the MCA Reds smooth.
I would be hard pressed to pick between the MCA Reds and Xidas, but if I had to the MCA Reds would get the money only because the ride was a little less harsh. Yes if they used the same spring rates and the same car the 'result' maybe different. Makes me rethink if a track car really needs stiff springs and a harsh ride, made me miss a stock NA6. Did not help when the car with the MCA Reds had my old dash in it, was tempted to take it back
Hopefully a few people who drove my NA6 today will give some feedback. Certain person managed a 1:25.7 for the happy lap session ... I also have the top speed reached