It's not really a case of which map 'needs' certain hardware (not unless you're in the numbers game, which you could call 2+), more that different configurations of hardware deliver different results (in terms of torque curves and power delivery).
The various advertised/marketed stages are somewhat a distraction from the reality. It's quite a new thing (last ten to fifteen years maybe) to label certain maps 'Stage 1' or 'Stage 2+' or 'Stage 4', or whatever.
The reality is that the decent custom mappers out there can map a car close to its safe potential based on its specific and possibly unique hardware. Just like years ago. And years ago, tuners didn't push the 'Stage' marketing thing. It's just labelling.
So look at it this way:
Car A has a standard exhaust, and uprated pump. It makes 260bhp peak power, and 350lb/ft peak torque after a map. A while ago it was called a tuned car. Today it's called a 'Stage 1+' or whatever anyone wants to call it.
Car B has a full aftermarket exhaust, and standard pump. It makes 270bhp peak power, and 330lb/ft peak torque after a map. A while ago it was called a tuned car. Today it's called a 'Stage 2' or whatever anyone wants to call it.
Both cars are quick - probably equally as quick as each other. Just because car B has a 2 in the label it doesn't necessarily mean it's quicker than car A that only has a 1 in the label.
Don't read too much into the 'Stage' labels. At best, it's a rough guide. At worst, a misleading marketing trick. I used the labels in the earlier post as a rough guide.
Generally speaking, '+' in the labelling denotes the presence of an uprated fuel pump, which can function happily alongside a standard exhaust setup. Hence 'Stage 1+'.
Stage 2 denotes the presence of a full exhaust, ie bigger a downpipe fundamentally, which can function happily alongside a standard fuel pump (in most cases, fuel cuts depending). Hence 'Stage 2'.
I'll just clarify regarding the hypothetical power and torque figures above. Increasing flow and increasing fuelling give different results. You need to consider the curve, rather than peak figures; although the suggested peak figures were intended to give an indication of the curves, comparatively. Combining flow with fuelling... well that's the numbers game. AKA 2+.
Final edit. Might as well add this little reminder if anyone's still scratching their head:
Anyone wondering why a car with 350lb/ft peak torque might make less peak power than a car making 330lb/ft peak torque - it's all about where in the revs the torque is made. There's a thread on this, that I can't be arsed to revisit, but search the term 5252 and enter the rabbit hole if you want.
