If it were me, I'd install the kit, and make sure I have the lightest spring possible in the waste gate. Install wideband o2 for tuning.
Then I could start learning the tuning software\under just a couple pounds boost. Then add Bigger injectors, and tune. Rebuild motor with expensive parts, up boost, tune, and hang on to your shorts.
This, of course, is if you want to do your own tuning. The tuning is a bit of a steep learning curve, but more rewarding and you should end up with a more daily driver type car.
If your not going your own tuning, I'd still install the kit first and try to find a extremely light spring for the waste gate. It's nice if you have the time to go one step at a time working out the bugs. Very easy to trouble shoot. I'm sure even with a pre-built system there will be bugs and unforeseen things that will happen.
My motor is a detonating machine, so I installed a J&S knock sensor and it was probably just as valuable as a tuning tool as the Wide band. It sounds expensive, but down time of a daily driver as your replacing head gaskets, collapsed pistons, etc. carries a huge cost. You are walking a tight rope on timing/boost for max efficiency, even with a built motor.
When you start putting the build, please do a build thread. I'm always interested in others experiences. My experiences are just what I have found out the hard way in my application. I'm hoping that its a very smooth build and easy tuning for you.
stock block 347 w Bullet Forged flat top pistons, TW170 p&p heads, comp 35-775-8 cam, approx 9.6:1 compression, 72mm rear mount turbo, injector clinic 650h injectors, CircleD 2800 stall converter, Lentech valve body.