what are you guys using?

I am looking to build a brushless 1/8 buggy to race with the nitro guys at the local track next season. I am not sure which car I am going to get yet,
but I need to put together a combo that will run 30+min for the mains. I live at 4500ft altitude so I only need about 36mph but 40mph would be excellent.

I am thinking of these cars Losi 8, RC8 or the new Hyper 9. I normally race FE Boats so I have a bunch of this stuff!

setups I am thinkin of:

4s1p 5000mah or is 2p needed?
Mamba Monster esc
Neu 1515 1y
Nemis/ Feiago 8-9XL

Thanks Sean