A very nice DIY--I did it myself, too. Took me about an hour--probably faster if using power tools...
Here are my comments on the process:
1) You had better use a guide wire/rope when pulling the old cable out, or you'll be in trouble.
2) Taking off the lower kick panel is necessary.
3) That firewall grommet is a pain--but it's soft. You will need to move the "black box" out of the way to get down there (uses 10 mm bolts, like 90% of the bolts on the Acura). I found that needlenose visegrips to pull on it, and a dull regular head screwdriver to kind of pry and pull (look at the new firewall grommet to see what you are prying) it got it out after 10 minutes of work.
4) A flashlight to see down in the footwell, looking up at the firewall, is very handy.
5) It is necessary to take off the instrument cluster bezel (4 screws), and then remove the instrument cluster (4 screws and one or both of the wire harnesses) to see the back of the speedo and clip the new cable in securely. Your tilt wheel will come in handy at this point.
6) Sliding the seat back and/or tilting it will help. If you're not a hefty guy you should be able to lie back into the footwell and mess with the grommet.
7) That boot on the transmission end is a real PAIN.... I messed with that, and that part alone for 2 hours today, trying to get it on over that clip! I suppose that age has made the boot not as elastic as it once was, but I just can not get it to stretch over all three "points" on that clip. I can get 1...I can get 2...I can't get 3. Grrrr...so I left it covering 2, since I was losing light, I was grimy from lying on the engine, and my arm was hurting from where a heater hose clamp dug into it every time I had to push on that stupid boot! Is there a solution?