lines dont need changing unless in real bad state which is very very slim chance, a 282 disc will be fine until you get to point where your doing a track every couple weeks
i never liked oem ek4 brakes even on road so understand why you want to change, ek9/dc2 braking system is much bettter then ek4 (abs is different and you can feel it (superb), 282 fronts and 262 on backs opposed to 262 and 242 on ek4, bigger caliper/piston on front, better oem pad compound, larger rear pad on ek9/dc2 and bigger mater cylinder to cope with the extras
run your brakes into ground then just sell you calipers and buy new calipers, discs and pads from dc2/nsx/legend etc and only headache you have is sourcing appropraite carriers from scrapyard (you could buy new but no real point cost wise)
lines dont need changing and ek4 master cylinder will work but for better pedal feel and little less trvel get dc2/ek9 master cylinder + couple bottles brake fluid and you have proven new setup (pad choice can be daunting but down to setup/driving style/your specific requirements - most good brake companys will discuss pads with you and recommend 1 from their range)
£600 for all new bits, you could prob fit yourself or pay £50 to garage to fit, savings there to be made with lesser discs, pads, used master cylinder etc, dont skrimp on used calipers though as usually bites you back years later