If you build the car yourself there is noway it will cost anywhere near 15k. I am assuming you have the motor already and dont need too buy them.
YOu can price everything out
GE sleeves are 750.00 plus shipping 100.00 thru
www.camp1320.com
Pistons range 450-500 Cp but you can get Je for like 300
Eagle Rods are 280.00
Headgasket 90.00
ARP headstuds 100.00
Oil pump@ water pump 160.00
timing belt 50.00
That bottom ENd 1890
Ok now the head
Supertech Valves,springs @ retainers 550.00
Labor installing them going 1mm over 400
Intake manifold 280.00
total 1230
Now as far as the turbo kit it just depends on how crazy you wanna go,
Usally we can pieces a whole turbo kit toghter for 2500-3000 that includes hondata,it just really depends how crazy you wanna go with that.
Not all head need to be port and polished, altough i dont know much about D series i know B series will hold out just fine. And if you look at the full race car, the built motor that did 460 blew up the night before the race and they installed a stock motor, so when he was on pinks that was on a stock D series motor, not the built one!
And if you feel like spending 15k building your car let me know ill sell u my whole car for 18,500 and it has everything you can dream of!