2nd Gen R56 Cooper New to Mini's have questions on my newly aquired 2007 R56

I bought a 2007 R56 with some front end damage. I finally got the parts and put it back together and painted. When I took it out for the first time I found that I had a water leak.
I located it in the thermostat housing. After finally getting it off, I tried to order a new one but found that the parts houses show a housing with 2 outlets and a filler cap, mine has 5 outlets and a pipe with an o-ring seal. Also they show a short lower radiator hose mines like 5 feet long and goes from the left of the engine to the lower radiator outlet. I'm getting very confused as to what engine it has DOHC or SOHC it looks like a DOHC spark plugs in the middle of the head.
The mini store shows the proper thermostat housing but the radiator hose is wrong. I switched to an S model and it shows the radiator hose but the thermostat housing is wrong.
Seeming I'm ordering the parts online I want to be sure I have the right parts.
Any suggestions as to where to order parts from?
I'm going to put brakes and rotors on it too don't need HiPo but want good brakes. More confusion what size rotors does it have.

 

Thanks for the start, I'll be using RealOEM quite a bite till I get this running the way it should. ECS Tuning has very competitive pricing. Always looking for a better price.
The sponsors are right there too.