Let me bring some real insider news(don't ask me where I got it and who I am but you will see)
Start 2nd half of next year, N55/N55HP will be replaced by an newer version of N55, power goes up ~10-15% and will start with F32, F10 LCI and F15 X5(Sorry, no F30 sedan), then all cars with N series L6 turbo in the next 2-3 yrs. This will reduce the SKU and hence lower the overall cost.
The next all new N series L6 turbo engine under R&D now is coded N58, displacement very likely stays the same but while its N55 predecessor uses a single twin scroll turbocharger, the N58 is going back with twin-turbochargers again however with one twin scroll turbocharger and the other one not!
Power target is 370-400hp range. It's going to hit the market between 2016-2018(2016 the earliest), which is the perfect timing for all new 5/X3 series, F32 LCI, F15 LCI, all new 3 series, etc...
V8 engine will stay pretty much the same, which is the current N63tu, it will replace all N63 next year, though will also get minor tune here and there and goes to 500hp club in the next 3-4 yrs. Currently not sure if displacement will stay the same after 2-3 yrs but as far as technology is not going to be any major changes.
There is also a diesel engine coded N59 under R&D but I am not a fan of diesel so not even want to bother.
OK finally the F82/F82 engine! It's L6 3.2L. Output is between 440-455hp. However starts with MY16 the earliest, it will come with optional power pkg which will raise to 470-480hp in order to give enough gap between the new N58 engine. Though the Power pkg is not just simply increase the boost, it's more about better intercooler liquid and better designed air-to-water system together with upgraded intake/exhaust(so the pkg won't be cheap). F80/F82 engine also has the largest ECU file amount all other BMW models, which is 35MB. The new liquid intercooler holds full 1.5 gallon(or liter, i didn't catch it very clearly) of coolant , and will always keep the air temp below 35C.
Below is what I got from the insider(NOT from any websites or news), but unfortunately is in Chinese. Whoever can read it can clear see how the liquid intercooler is being designed and hopefully someone can translate them all! It's so exciting to read but too professional to translate!!!
3.2L L6涡轮增压引擎，预计最终发布第一年款还是440-455hp不变(最终值还在调校)，但是最早MY16开始加装套件后可以抵达480hp。由于两只涡轮的设 计，宝马放弃过去的中央进气口（N54）改为两个独立进气系统。它的水冷中冷器不陌生了，F1 0 M5上有类似的设计。里面的管路设计是一个类似物理学上的欧姆的符号，从前进后出，充分利用了水的冷却性， 里面是中间对半分，这样子可以分级冷却，冷水管是进去后从一个Y型阀门分成两路分别两级冷却。这样子即使是 40C的高温，依然可以保证进入气缸的气体小于35C。
中冷是上下两层，每一层对应一个涡轮，一个进气管道负责其中的3只汽缸，这三只汽缸是135或者246。现 在在原来的中冷位置只需要另一个冷却系统，这个系统和汽车的冷却液是一个概念，不同点在于它的液体压力不同 。在略下方还有一个油冷，给涡轮轴散热。另外之后的480马力套件很大程度上来自不同的冷却液和改进的中冷 管路以及优秀的排气系统和Cold Air Intake，外加上更好的底盘调教和传动系统调整，而不是很多人想到只是刷ECU解决(所以估计价格不菲 )。