We have ISTA and bmw key reader. yes you can access it and register without having ista diagnostic tool. the only thing is unless you reset the service light etc using ISTA tool it wont record it on the cars display which to be fair most customers arent bothered about. in all fairness the genuine bmw tool is only £500 to buy
I bought the bmw key reader which i thought you needed to transfer data to car. not the case the key reader purely reads service data from key. to key data onto car you need to do reset with ISTA dealer tool
sean