I have not found a website that describes exactly which fragment of data is represented by VIN position 4 - 8 but one of these websites should help:
http://www.dmv.org/vehicle-history-reports.phphttp://www.decodethis.com/The "T" in the second position of the VIN represents the manufacturer instead of the brand. T = Toyota
The third position ("J") apparently represents the Lexus division.
The main thing I remember from working with VINs at the insurance company from which I recently retired is that VINs sometimes do not contain enough information to charge an appropriate (i.e. high enough) rate. The VIN does not describe all the options a vehicle may have.
I suspect that the people who came up with the idea of a 17 position VIN have been kicking themselves ever since for not making it longer to allow the inclusion of more information -- but it is way better than the 10 digit VIN that was in use when I got into the business.