Originally Posted by Mr Wrex
If you're doing the vf39, your stock injectors should be good.
Things you'll want/need to add:
1) fuel pump
2) boost controller
P.S. My name's also mike. Too many dam Mike's in this world
Fuel pump isn't needed, WRX/STI pumps are the same. Boost controller is the same, doesn't need touched. Heat wrap would just be for fun.
OP, to go with a VF39 you would need only the turbo and at least an STI TMIC. Otherwise, you are good to go. If you go 16/18G you can get away with keeping your injectors and pump, but you want to upgrade if you do go that route.
Your wrx does not have STI internals per say. The only difference for 06 between the STI and WRX short block is the piston dish. So basically your pistons are different. Heads are different if you want to talk overall differences.
You do not need an up pipe AT ALL. Your stock one is by far good enough for what you want. The net gain is ZERO. It's not catted if thats why you wanted for "precautions."
I'm sure I missed some points, there was a lot of misinformation in here for what you originally asked. If you want reliable, stay with a VF turbo and simple tune. Meth will always run the issue of catastrophic failure to the motor, and an untuned turbo can do the same. You will not see 350 whp on any setup mentioned.