Varta's are hit and miss, but those problems could be the battery. You still want to look at the RCM though as that is a problem that needs to be repaired, and can cause the not start issue... Probably not the CPS, as they will cause the car to start run rough and die. Although once they go bad, they will let the car turn over but not start. So I agree with the above post. Start with the battery, load test it, move on to the RCM and finish with CPS...the CPS wouldn't hurt to be changed anyway as it is usually a $40 fix here in the US.