B or RB in A body

From what I've seen either works but the RB exhaust choices seem a little better. They Schumacher tri-y headers and the TTI headers both fit a little better on an RB than on a B. They fit and work with either, but you have a little more room around the suspension, starter and transmission with an RB. Of course, with the RB you have less clearance for the hood, heater and master cylinder. There are more intake manifold choices for the RB and main bearings are easier to find. I'd say it is a bit of a coin flip.