Nissan CAS sensor has is optical. You have a 90deg output and at 360 degree. One of the 90 degree markers is longer and signifies TDC.
Do NOT knock a piggy back ecu, I use these all the time and they work _VERY_ well with nissan ECCS.
I have for example over 5 gtirs now pusing 450+bhp on e-manage blue, and many more in the high 350+bhp. I also had my own Micra upto 180bhp from e-manage ultimate and there is much more to come once the engine is made capable of this.
Infact I would guarantee I could match or exceed whatever you tried to do with an aftermarket ecu, with an e-manage.