Hello everybody nice to see a new Landy forum.
I was posting this question in LRE and "proctoriv" (hello Ivan!) tall me about Land Rover Addict.
So here is my questions (maybe someone have read it already in LRE).
I'm in the way to fit a Optima dual battery system (red/yellow) with a IBS Split System, in order to handle the winch, extra lights and a improved sound system and some other things that will come later… 

I have few questions and doubts. 
Wen a bought the car was coming with a Warn M8000 connect to the original battery. I should connect it in the secondary battery, right? some people tell me that and some others I should wired in the main. What is the best? 
Another issue with the battery and winch is I should install a isolator? Why? 

The car also was coming with a Webastoo I should wired in the secondary battery? 

Depends of the total watts I will install in the Audio I will have to think in the alternator, just in case I will like to know few things. 
The alternator in a Defender 110 TD5 (2001) is rated a 120 Amp. Is that right? 
If I need it, can I fit a HO Alternator keeping the 12V, whitout to melt all the cables? What is the max limit Amp? Maybe that is a silly question bud I saw alternators at 375Amp 12v. 

Thanks a lot
Salva