I was thinking about experimenting with something like this, but then I realized that it isn't that simple. The steering ratio is more than just the gearing in the rack. 12.8:1 or 17.8:1 is the ratio of steering wheel angle to tire angle. This means that it also includes any difference in the length of the steering arms on the hubs (a shorter arm would make a quicker ratio, but you'd mess up the toe-steer unless you also move the rack forward)
The Evo FSM claims 2.1 turns lock to lock, a 146mm rack stroke and max tire angles (degrees) of 32 inner, 27 outer (the tires steer differently because the tie rods are not at 90 to the steering arms - so the car can turn at low speeds without scrubbing the tires - it's called "Ackermann" steering). If my envelope math is correct, that means the distance from the tie-rod to the hub is about 5 inches.
Measuring the other day on my car, I also got roughly 5 inches from hub to tie-rod, so swapping it might work. You'd have to figure out the stroke of the stock rack though. Keep in mind though that you'd lose low-speed turning radius if it actually matters to you.
One thing to keep in mind is that the Galant has a higher available steering angle than the Evo (37.5 inner, 30.5 outer), so just comparing lock-to-lock isn't accurate. Does anyone have an accurate lock-to-lock estimate for the Galant? I remember reading 2.5 or 2.6 turns somewhere for a DSM but the 1G has max steering angles the same as the Evo. The Galant AMG had a 2.7 turn rack (14.3:1) which is quicker than the VR-4.
If our rack is actually 17.8:1 as claimed (not by anywhere unofficially unfortunately) it should be 3.4 turns lock to lock. Has anyone paid attention recently?
If the galant is actually only 2.7 turns, that would make a 14.3:1 ratio, so maybe it's more? The VR-4 Evo and RS models supposedly had 2.4 lock to lock, which is actually slightly quicker than an Evo rack (12.7:1) /ubbthreads/images/graemlins/jawdrop.gif
