ok, so you have P8, and not PP 2010?  i ask because the IDL solution is actually kind of tricky.  it makes linearized and not corrected output.  so if you use all IDL ready materials, your end result will look too dark and saturated unless you find a way to correct the final, post IDL results.  you can do that with bagginsbill's Artistic Lens trick, or just figuring out a way to filter the final render.  i don't have P8, so i can't test this process, but i think i would  personally do the final render and then use the Artistic Lens trick on the render.  that way i'd still get smoothing, not have to boost the raytrace bounces just for a post-production filter, and still get the final result i want.  and i'd just use the Artistic Lens trick for test renders, where i could deal with the loss of smoothing and such, but would see accurate lighting.  but it's non-trivially complex.