i take it to get the front and roof etc you extrude the edges?? if so when you do the front, only bring it out a little bit, and move it forward a little, then go a bit more and so on.. this creates a lot more rounded corner to it rather than jus a 90 degree bend from side to front, ill post a pic to show what i mean. btw nice roll cage [attachmentid=6547]
on that pic you can see were i have extruded and brought it all in so that the bottom part of the roof is bent in.
[attachmentid=6548]
Here you can see how ive made the front rounded by bringing the edges out.
As far as i no you dont need a text porter to skin in 3dmax 8, Dont use unwrap uvw as this will warp and distort the skin totally and will end up looking cack, use uvw map to skin it.
Hope all this helps and btw, dont map it untill you 100% finsihed and happy with the model