S/C 4.6 or Nitrous 5.4

Alrighty guys im stuck. no matter what i have to build and engine. my stock 4.6 has 133k on the clock and im not comfortable putting any type of power adder to it.

So.. do i re-build the 4.6 and put 03-04 heads and blower on it. or do i build a fully forged 5.4 with some decent cams and spray it?

Lets hear what you would do?