All the team kit needs to be super competitive and reliable is titanium turnbuckles, titanium ball studs and nitride shock shafts, i would honestly go the factory team kit, it has the plastic chassis now and by the time you buy Ti turnbuckles and shock shafts etc. you are only a dollar or 2 short of the factory team kit which has even more goodies.
Lipo is awesome man, dont buy Nimh unless you are planning on running at state/national level and you need them for legality reasons, Lipo has a lot more power, run time and the ease of being able to charge them as many times a day as you want and also leave them charged up for weeks before hand without the need to even re peak them is the selling point right there, plus they never need cycling. Need i say more?
For the setup you will be running i would go for Orion/Peak carbon edition 3200 or the new 3600 packs, they are a good price point at around $80 a pack, they are Kokam cells which require little to no balancing at all, they are i direct fitment into the chassis and have protective casings, perfect for first time Lipo owners. I run them in my B4 and they have insane power with the GTB/7.5R motor combo i am using, wheel stands are almost a common thing everywhere on the track if you are trigger happy, thats on the verge of to much power in anyones eyes if you ask me. When i ran the same combo on 4200 matched NIMH cells it had no where near this amount of power. Lipo all the way. You will need to add weight for the Lipo but for stock you might get away without adding much, this thread explains where and how much to add f you do add some.