They are craftsman level kits so if you are not willing to clean up the edges (window openings, along the edges of the walls, along the corrugation, etc) there is no point to even trying to make such a thing... period.
The kits are kits in the truest form. You have a .020" thick clear inner wall that will be used to give oomph to the sides when they are handled. And you have various parts that will have to be cleaned up and painted before assembly (with some masking required so as to provide for a really good bond). Typical bonding agents such as Styrene Cement cannot be used because of the thinness of the side parts (typically less than .005") but IF you are up to the challenge the value of having an unique car is worth it.
When I first wrote the N-scale Varnish Passenger Car User's Guide I didn't include U.S.P. because I was unsure of the product but after gaining a kit I went through and added them to all the lines that the company represents. They are not for everyone... heck they probably aren't for more than 5% of all N-scalers given the difficulty in building them... but if one chooses to pursue the challenge the results can be very nice... very nice indeed!!!
