MVee,
You do lose some pressure over the distance of piping. I don't know if it would be a factor in the several feet of piping from the back quarters to the motor or not.
One thing to do if you are going to DIY your on turbo, get the book "Maximum Boost" by Corky Bell. I believe in there he has the formulas to calculate things like pressure loss over distance (and diameter of the pipe).
The Mazda is pretty much a hand full and is only really fun on the track (when it isn't overheating). On the street it is a traffice ticket or accident or both waiting to happen. Like walking around carrying a hand grenade and the pin pulled out--you have to be careful all the time. If you get hard on it you are ready to go to jail by the time you get it out of 2nd gear.
It is fun, you just have to pay attention 100%--is the road wet, are the tires cold, what is that old lady 500 yards in front of you going to do. You have to think about all that before you pull the trigger. The only way you get turbo lag is if you are in too high of a gear and it is lugging already. Otherwise it is pretty instantaneous.
