How much work is involved in getting a nice model working in the game engine

If I were to select a nice model from (example: a car interior with say 150,000 polygons) built for the Blender Renderer, roughly how hard is it to get that model working in the game engine (for an experienced modeler)?

In particular, I want to use the game engine for a very simple demo where 2 spotlights move around the interior of the car dynamically (based on external input). It’s the most simple possible game requiring >20fps rendering.

I know a little about blender, but I don’t know what to expect in this regard. Could someone help set expectations for me?

retopo the car to low poly and bake maps to it from high poly and it will run at 60 fps

atomicskill leon in Facebook blender game engine group makes pbr looking car shaders using glsl nodes

Ok, so I could hope to get something looking reasonably close to the original if I did this right?

This is a bit beyond my own skill level, so I might ask a freelancer to do the work. Could you give me some ballpark estimate of how much time I might expect it to take?

I might guess a few days of work from an experienced modeler given a nice high-poly count model with the goal being a game engine where UP/DOWN/LEFT/RIGHT control a spotlight moving around the vehicle interior. Does that sound like a reasonable expectation?