The N1's are a smaller turbo. hence producing less power, but being more responsive. If your after low-mid 300kw's the N1's would be perfect (same with HKS GT-SS). Price, well for a pair of HKS 2530 they are about $3500 from nengun.
Have a look in the forced induction area, up the top in the stickied section at the Rb26 results, fair few people have posted results using both these turbo's