[mr0077]

Kim, to answer your last question (that may have gotten lost in the ensuing shuffle/scuffle), having a shoulder belt/lap belt combination is absolutely better than a lap belt only (with the exception of some very extreme, highly unlikely possible situations). For street use, you should take a look at BMWs, Miatas, etc...production convertibles...that typically have the upper shoulder belt attach point below the driver's shoulder, mostly because it will pass DOT and they don't want to put a higher attach-point on it. The 300ZX added a higher attach-point for their car.
Wayne, for racing purposes, the belt/restraint requirements of the various sanctioning bodies are very good, but they aren't necessarily appropriate for street applications unless the structure of the street vehicle can withstand the forces imposed by the restraint system. With street vehicles, things start coming apart at 60-70 mph, and a 3"x5-point system could likely be found in perfect condition, but totally ripped loose from the car. Without roll cages and other intelligent safety upgrades, the 5-point is only marginally better than the 3-point.
Go with a three-point rather than a lap belt only.