Are the Vf30s quite an agressive turbo? (still havent put mine in, the VF22 is still gng fine)
vf22 more top end but will come on so very slightly later
you dont need to change ecu by changing to 2.5. you can run standard with no problems
Edit: your stock loom will be fine, just bolt all of your gear onto a 2.5 with correct gaskets = happy days