I just finished yesterday with my conversion. I'm using the SC8 stock towers for now. Maybe carbon fiber if all goes well. I will be using RC8 front shocks all around since I already had them with DM1 springs. These are not the bigbores like you have. Kyosho has 16mm shocks so the springs fit.
I race at a good size track so a 2 speed is necesary. I'm using a mix of parts from Thunder Tiger, OFNA, HPI and Traxxas. All this to use the stock center shafts since this would be too hard to make it right. I will be using Losi front bumper like you mentioned as for rear bumper I dont think I will use any. The new RC8 arms are not yet available so we will have to wait and see.
If all goes well I will try it tomorrow at the track but first I have to complete the brake-in of it's motor. I will use an EB Mods Hellfire .23 full mod motor to see how it performs. This should be ome quick car, the only bad thing is that I have custom made gears so I have to have a few prepared just in case since no one will have them. I will post pictures soon.