As for rods Eagles outta the US are cheap. As are Tomei rods as well at the moment.
With regards to the H vs I debate, read this thread and decide yourself (or simply talk to your engine builder?): http://www.skylinesaustralia.com/forums/topic/173552-h-beam-vs-i-beam-conrods/page__hl__beam
Apart from that I think you'll be hard pressed to make 750hp on HKS 2540s
HKS 2540s are a "mis match". One of the worse turbos you can purchase really. They will make a similar amount of power to a 2530 (~400rwkw), but with more lag, and they tend to be quite surge prone. Kinda like a GT-RS (new generation), especially on a 2.6ltr.