g751 / g752 is the best notebook you can get for a fair price. 16+gb ram, intel skylake, 980m/980 (yes desktop version in a laptop), 240ssd + 1 tb normal drive. and you get mobility as a bonus.
i've got mine g751 and it rocks.
though i agree with lennaert about having a slower system for testing purposes, i can tell you - unless you go crazy particles or heavy pathfinding with shitload of objects - no worries.
also if you're going mobile, buy s3/s4, and iphone 4-5 to test. because newer ones will work DOH.
oh yeah and
p.s. next week i'm gonna give a template to a PC game (sellable on scirra store) but i'll link the game's play so people can test their PCs / smartphones / whatever on my game. more on that next week.