Its not that big of a deal. Yes it is an interesting cross-over design, like a few other things on the car. Cross overs allow the exhause pulse running down one side of a slit header (front 3 and rear 3 exhausts) to form a vacuum in the other pipe: as the pulse passes the holes ( I don't know the count, maybe three or four 25mm slots a few mm tall, along the length of the reinforced area, what, 200 to 300 cm long?) The slots are like venturies in a carburator. As the hot gas pulse goes by, it sucks on the othere pipe. As the rpms change, the pulse frequency changes. So like a trombone the tuning of the pipe to maximise the vacuum changes, therefore multiple holes extends the range of effectiveness. Each pipe has pulses. The pulses are in synch but out of phase. The out-of-phase suction from one pipe pulls on the pulse behind it in the adjacent pipe. Its called scavenging. American V8's famoulsly had one pipe welded accross the dual exhaust somewhere down below but usually infront of the bell housing or behind the tranny. Now you can get prefab X's to keep the flow more purposefull and esthetic (X-over pipe). I like the idea of the multiple slots helping to tune the scaveging, but the OEM piping rusted up and became ineffectively plugged. And its a little heavey.
The stainless prevents the plugging. You also have the main muffler that mixes both sides. I had more than one muffler guy say don't worry about it the main muffler does pretty much the samething.
If you would like to experiment and think you might be able to tell the difference: put in straight pipes, then put in the correct X-over in stainless and let us know what you heard and felt.
Of-course, if its a show car it must be original.