After all professional advises and information given by dear members, the don and twin turbo, I gave up the idea of cutting the body and convert it to a mini truck, so now am very happy as I have lots of memories with this van, it is in good shape now. Thank u very much for your advices again. See some images.
http://img251.imageshack.us/img251/5251/p7230359.jpg
http://img682.imageshack.us/img682/6973/p7230368.jpg