All this talk of rod/stroke ratio is getting a tad annoying. It's not that simple. Basically you want to have straight up-and-down forces acting against the crankshaft (and thus the main bearings and bearing caps). The longer the rod in comparison to the stroke, the more the force of the rod moving is directed away from plain up-and-down. To get the B18C block to be reliable enough to rev to 8000 RPM and still meet OEM standards Honda installed a girdle which connects the main bearing caps together. Think of it as a strut bar for the main caps. With the caps tied together the force can be distributed over more mass, which lessens the effect of said force. It's an alternative to stepping up to stronger rod bolts and forged rods, which while semi-affordable to you the aftermarket engine builder, would present a good bit more expense to the OEM.

Now, if you're building up a B16 there's not much point in installing a girdle. All the stock B-series cranks are very beefy forged pieces. The rods are where you'll see a problem and since the B16 has such a short stroke there's a much more uniform up-down force exerted on the crank and rods. You really only need to replace the rod bolts with ARP pieces and install new bearings, plus make sure that the crank and rods are all within spec and you'll be fine out to 9000 RPM. No cams make power that high anyway, so the bottom end should be fine.

With an LS/VTEC you can either install a girdle with the stock rods, or step up to forged rods and ARP bolts. Either way the motor will take plenty of revs. The stock LS rods are no stronger than the GSR rods, yet there's no girdle and the stroke is longer. Needless to say they see more stress forces at the same RPM as compared to the GSR rods which is why you need to do some kind of upgrade.