Your stock injectors and fuel pump will be fine for the stock turbo.

Your $1500 is best spent on an ECU, or saving towards an ECU. For the $1500 ECU option you could get an EcuTeK which is basically a remap of your stock computer. Other option is to save a while longer and get something like an Autronic SM4 or MoTeC M800, both of which are about $3000-3500 drive in, drive out.

Hope that helps!

PS - I don't think you will get a flat 13 on the stock turbo in a GD chassis, but you will get a low 13 with all bolt on stuff done.