i have a 97 eclipse gs that i just got and i want to turbo it the kits are way to exspensive so im buying the parts separate so far i have

14b turbo
1g bov
2g gsx exhaust manifold
oil cooler
2g gsx fuel pump and rewire kit
2g gsx stock intercooler
all the water oil return lines

for a down pipe could i use the stock gst would i just have to modify the holes or do i have to go to an exhaust shop and get it custom made and for the exhaust manifold can i cut off the flange from my non turbo manifold then cut off all the mounting holes for the turbo manifold then put the non turbo flange over the turbo flange and weld it together