3ds Max :: Add Smoke To A Rocket Using Particle Flow

I've been trying to add smoke to a rocket using particle flow. However, while I have managed to do so, with only 400 shape facing particles (which look excellent), they seem to slow down the render about 10 fold than without.

The scene itself has 200,000 polygons with most, if not all, objects having mental ray Arch & Design materials on them. The particles however use a Standard material with particle age, gradient and noise maps. There is currently only one mr area spot light with raying shadows in the scene.

Also another thing is I would like the shape facing particles to be affected by backlighting but I've tried placing orange lights within the rocket boosters and this hasn't appeared to light up the particles in front of the booster towards the screen. I imagine the only way would be to use a material like mr Arch & Design to be translucent.