I would leave the stock MAP sensor and if he has 390cc Injectors already I would disconnect the V-AFC very carefully and just get the car tuned ..
Leave the boost to 8-10psi and pay to have the car street tuned . He's looking at around 250 for street tunning services if he already has the above mention chipped p28 and the injectors . I would recomend a Walbro 255lph fuel pump as well for saftey if he does not already have one ..
yea, has a walbro, so he's set for fuel.
so just get it tuned on the P28? sounds good...
both repped. thanks guys.