Dct should hold fine up too about 600whp and 700nm. Thankfully the big singles make a little less torque that upgraded twins. Anything past that you want to consider giving Dodson a call. I wouldn't push a n55 past 600whp without significant engine work.
Thanks for the advice, had a chat to Alistair from Exceed. Looks like the Pure turbo option is the best and simplest way.
Has anyone on the forum had any experience with Pure turbo stage 1 upgrade on the n55 ?