i dont know how people used to manage without all the friendly forums like here where there is always someone to share their valuable knowledge
I don't think they were even though of when I bought my GS and there were very few such sites when I ran a BX.
Never even thought of it when I had a Xantia but on the plus side I didn't really have many issues with it - heater matrix was the only one and I wouldn't have attempted that anyway. It always just worked and worked very well. It was a sad day when it was trailered away through no fault of it's own.
Sadly Xantias are becoming the new wave of BX's and no doubt as Jim says the forum will morph into a predominantly C5 one. Which is regrettable as in many ways I believe that the Xantia is the better car - the Activa unquestionably so.
With dwindling manufacturer support and no help at all from the government they will presumably take their place alongside the DS/GS/BX and be the sole preserve of die-hard enthusiasts.
Certainly the site and some of those like it are an invaluable resource, without substitute. The collective knowledge and skills are second to none and all based on practical experience - just as you have discovered
sportingfiat
And very pleasing too although there is very little I can contribute to any of them 
