Since you mentioned stock subframe I`ll stick to that. We`ve instaled and tested a few of the R&P conversions for the stock subframes and honestly I`ve never been impressed. It`s a really tough job stuffin a R&P into an envelope that was never intended for one and then making it work as well as a modern car that was designed around a R&P from the ground up.
The factory steering gear on the other hand,while certainly not ideal has had 40 years of R&D done on it and a lot of good has come out of that. The bumpsteer issues can be fixed with a bumpsteer kit or our tall tie rod ends and manufacturers like Lee have developed valving curves for blueprinted fast ratio Saginaw boxes that yield exceptional steering feel and control even by modern standards. This for a fraction of the price of a R&P conversion and a lot less work since you don`t have to mess with adapting the R&P input shaft to the steering column.
A quick word about Mkelcy`s reply. I more or less agree with it except for a few point on tubular arms. It`s not the tubular part that makes them worth having and some in fact actually do nothing at all (except look cool). Some alter the static alignment bay adding more caster and are shorter allowing more - camber at lowered ride heights. That`s a good thing because although it`s not really altering the geometry per se the alignment works hand in hand with the suspension to make the car work well...or not. When significantly lowering a car,when installing taller spindles or tall ball joints that effectively increase spindle height,or when doing the G MOd and especially when doign 2 or more of these things in combination the normally droopy stock arms swing upwards and also
outwards giving you a bunch of + camber that you have to get rid of. Considering that it`s usually not possible to align bone stock early Camaros to modern performance specs due to lack of room for shims on the rear stud you`re pretty much out of luck. Now you may have a car with some really good suspension parts on it that drives like a shopping cart because you can`t align it properly. Also watch the angle and travel of the upper ball joints, taller effective spindle heights,lowered ride heights,the G Mod and stock upper arms can contribute to putting the upper ball joints in bind before you achieve full bump travel. That`s not a good thing and can eventually lead to suspension fatigue and breakage most likely resulting in a very bad day.

To summarize,bolting stock spec tubie arms on a bone stock car won`t do a thing for you but using the proper A arms on a well modified car can make all the difference in the world. Mark SC&C