Personally, I think the criticisms people have regarding the ‘sound-quality’ of Reason (or any other DAW , for that matter) are more criticisms of the quality of the stock sounds and stock presets. There’s no real reason why your finished audio production will sound worse in Reason, if you use the same sounds as you do in any other DAW .
On the other hand I do concede that, in the early versions of Reason, the audio processing units could very easily suck the life out of any sound you put into them. Thinking back to the early compression unit and the early foldback distortion unit, it’s really easy to make good sounds terrible on those, for example.
Also, it’s worth noting that, because Reason is so unique in DAW terms (a DAW build entirely around emulating a physical studio), it’s quite easy for people to make mistakes that aren’t as punishing in other DAWs/Plugins, like pushing sound levels too high pre-fader. In an entirely digital environment, this isn’t such an issue. If you max out the volume output in, say, NI’s Massive, but make sure it’s not clipping on the mixer channel, there’s no problem. In Reason, the sound would still be distorted.
Check out this snippet from a Sound On Sound article on Gain Structure in Reason:
Although you might think this is an ‘old school’ topic more suited to analogue studios, ‘gain structure’ is important in Reason. This is the art of keeping all the devices in your studio running within their optimum volume levels. In a digital environment such as Reason, the main imperative is to keep levels fairly high (for maximum resolution), while preventing signals from hitting the top of the range of values that can mathematically be represented within the software. Straying above this range will result in flat lines at the tops and bottoms of your waveforms (clipping), which doesn’t sound pleasant! You’ll probably have clipped the main output from Reason at some point, resulting in the red clip light coming on in the transport bar. However, you can clip signals at many points before this within Reason. The output from any instrument can clip, for a start, and turning that down in the mixer will not help because the problem lies before the signal gets to the mixer inputs. Mixer inputs can be clipped. Effects devices that you’re sending signal through can be clipped. The main mixer output can clip. In other words, watching the red ‘Audio Out’ clip light is not enough; you need to be in the habit of setting up each device so that it receives and outputs a decent level without maxing out.
One thing to bear in mind, especially if you’re used to working with an analogue mixer, is that, like most digital mixers, the way in which signals are mixed together in the Reason mixer follows slightly different rules. All the individual channels are summed together into a stereo signal known as the mix buss. This is what arrives at the master fader on the right of the 14:2 mixer. Intuitively, you might think that if you mix together two signals that are almost at the maximum level, the mix buss signal would ‘go over’ and clip, but this is not the case. Reason uses 32-bit floating-point maths to sum the signals together, which means that there is an endless amount of headroom on the mix buss. The master fader scales this final signal down without any loss of audio integrity so, if the final output of the mixer is clipping (showing red lights on its meters) you can pull it down as far as is necessary to get a clean output. If this means that the master fader is quite a long way down, this isn’t a particular cause for concern, as it would be with an analogue mixing console.
So, to answer your questions:
1) As long as you make sure that there is no clipping in your signal chain in Reason, before rewiring the sounds into Cubase, there should be no problems whatsoever.
2) When you Rewire Reason, you run it in ‘slave’ mode, with the main DAW (Cubase, Live, Logic, etc) being the host, or master. This means that any changes you make to the length of the project, or the loop markers in Cubase should be reflected in Reason automatically. So exporting projects shouldn’t be an issue if the selected regions to be exported are correct.
3) You can certainly do that. I’ve done similar things before to make use of higher-end audio processing plugins in a different DAW . But make sure you remember that the same principles apply as with rewiring. Make sure that the original, source sounds in Reason are of good quality and not clipped or distorted in any way.
Hope that helps! 