restoring87

I am new to nodding out cars and I own a 87 rx7 turbo 2 I'm going to swap my turbo out for the s5 turbo and push about 12 to 13 pounds through it, I also have a front mount intercooler that i am putting on it, my first question is will this hurt my horsepower since the piping is longer, next I want to learn about the ECU upgrades, I've been told I need a fuel cut defender, does this not come with upgrading ur ECU, also with all this done will I need to upgrade my fuel pump and injectors? Please explaine to me wut id need to do to get to 350 horse power or 400 off stock motor.