Space is too restrictive for all the work you're talking about. Increasing the piping from 1.25" to lets say 2.5"-3" would obviously see gains, but good luck fitting it.
The costs would outweigh the gain. The other thread that's being mentioned tried that, but it looked absolutely ridiculous IMO and cost well over $700 for just piping.
These motors already make decent gains on stock turbo, so the extra 10whp isn't worth all that trouble. If you went with a different set-up than it may definitely be doable.