MTM2.com

For #1 I am unsure what you are asking so I will let someone else help you there. as for custom textures you might want to refer to this link

That page shows the specifications for single textures. If you want to read up on tips I would recommend almost any texture related tutorial by Winterkill. Here is a link to the one that helped me the most:
http://www.geocities.com/TimesSquare/Corridor/9018/textures/tutorial.htm

and if you need a version of psp there is a version still up on this site i think here

hope i helped

That's three questions.

http://rhinoseros.com/~mtmg/traxx/altitude.html

http://rhinoseros.com/~mtmg/templates/
http://rhinoseros.com/~mtmg/addon.html
http://rhinoseros.com/~mtmg/slice60/

http://rhinoseros.com/~mtmg/models/Custom/cbillboard1.html (get the traxx bb)

But if you really want to save yourself some trouble, bookmark this address http://mtm2.com/~mtmg/ and do some reading.