Why is the download so much larger than Version 4.0?
Parts&Vendors 6.0 uses the Microsoft Data Access Components (MDAC) and MS Jet 4.0 as its "database engine."  To preserve the integrity of this complex collection of programs, Microsoft insists that they be installed in an "all or nothing" fashion.
Including these large components in the Parts&Vendors setup program approximately doubles its size, relative to that of the P&V-specific modules themselves.
The good news is that many newer computers already have these components installed as part of the operating system, particularly some Windows XP and Windows 2000 systems.