1) Are you sure it's 3.8mm head gasket? I've never heard about such thickness. If it is really the case - it's pretty much insane anyway.
Your best bet is to get 1.8mm apexi gasket - http://www.rhdjapan.com/apexi-metal-hea ... 3s-ge.html
2) Orange are probably chinese injectors from ebay
3) Cast iron can be welded, there is no off-the-shelf manifold available for turbo 3s-ge.
4) Just plug it in and start, turbo map will not harm your NA engine.