XB HKS turbo kit, on an echo

[taKuto]

Well i've purchased an HKS turbo kit designed for the scion XB, and am in the process of getting it fit onto my echo.

The wiring is the easy task since I finally found what looks like a wiring diagram for the fcon mini piggyback off some russian site.
f-con mini piggyback pinouts

From the looks of it,
- HKS uses garrett turbo, I can't identify much else from the nameplate :(
- the oil feed taps from the stock oil pressure sensor location
- this piggyback modifies the TPS signal, guessing it sets TPS to 100% to get open loop, otherwise I'm not sure why else it'd modify TPS.
- missing oil return hose, probably could source one local
- I'm missing all the brackets that comes with the kit, according to this picture of the stock kit:
http://ep.yimg.com/ca/I/wotmstore_2170_140241189

A few questions I hope a few of you knowledgeable guys could help me with:
1) How should I check the condition of the turbo to determine whether I need it rebuilt?
2) This kit is not intercooled and has no BOV. From what I understand, this kit boosts to 4psi. Is a BOV required for such low pressure?
3) Not water cooled, should I be concerned about anything?

Intercooler is another issue, I will eventually need one (previous owner had lots of issues of overheating) but I will save that for when spring rolls in.

Here's the photo album, didn't post the pictures in case the account bandwidth gets used up.
http://s85.photobucket.com/albums/k45/taKuto11/snail/