Welcome to HAN! You have a mighty big budget to do what you want. I prefer the 92-95 body myself but you can do it with any civic really. 300hp out of a civic really isn't hard, a built D16 can do that, but with your budget I would get a B18 to build up and make 450+. There are many people on this board that will give you better advice than I, but I'll try to give you an idea. A stock manual Honda transmission can handle about 350hp. Most of the off the shelf turbo kits will be crazy over priced and likely too weak for what you want. Consider piecing together a kit. www.homemadeturbo.com will help.

turbo
manifold
wastegate
intercooler
piping
Blow off valve
boost control
pistons
rods
ARP bolts
MLS head gasket
Tuning software (crome www.pgmfi.org )
Injectors
Fuel pump

there is more but that should help you get started with some stuff to look at. some of the other members will add to the list and maybe give you some sites to look at for parts.