Sandblasting/ Materialblasting?

I have done a fair share in the past for my boss on his RWD Grand prix and blasting his rear end from a 300z and his old engine sub frame. I am in the same boat with wanting to blast my engine Sub frame and rear trailing arm, but I am also wanting to do my entire under carraige as my project car saw winters from 99-05. It has some problems spots with surface rust I want to take care of before they rot out and now is the time while its completely stripped.

I was using Black Diamond 40grit with my boss's car, and figure the same as much for my sub frame, but the actual under body is what I am wondering what I should use as the black diamond is really harsh. Here are some pics of the problem areas.

http://img176.imageshack.us/img176/8818/20080517image0026mt7.jpg

http://img230.imageshack.us/img230/3747/20080112image0002dy0.jpg

http://img265.imageshack.us/img265/4679/20070716image0006it6.jpg

http://img131.imageshack.us/img131/444/dscf0702gf2.jpg

http://img208.imageshack.us/img208/7995/dscf0707rm4.jpg

Its not really in that bad of condition for being a 99 with 40K original miles, just NY is really harsh on cars. I have new fuel lines and brakes lines out of my 03 parts car which are mint along with the new plastic tank GM put in these 00+. So any help would be appreciated. Thanks!

you should be ok, just move a little quicker with the gun to avoid heat warping the metal

white silica sand will give you a smoother finish texture, I only use black diamond for heavy cast pieces, like rear differentials