I would weld them at the least.... i have ripped torque boxes on the street with drag radials. its much easier to weld them and/or install battle boxes BEFORE the torque boxes get beat up than it is afterward.....
And I agree with MrXCESSIVESPEED. I haven't done any damage to any yet, but I've always had them welded and used battle boxes before anything could happen. I've heard they are a pretty big ordeal to fix once they start pulling away and getting ripped and all that.
And I think these are very overlooked....
I've seen people twist the tubes in the housings because they weren't welded up like that and it's not pretty either.
I twisted the tubes out of my hosing. Took me a while to figure out what I had done too. Rather than welding them and risking bending the housing from heat we actually drilled and tapped the housing and bolted the tubes to the center section. It's been like that for years now and I haven't had any problems with it.
I will also say that it's better to at least weld the boxes even if you don't put the reinforcements in. I tore my uppers clear off the body and spent a lot of time fixing them. Do it before it's a problem rather than after like I did.
It does seem that the uppers get messed up before the lowers. Considering your driving habits, I think you'll be fine though for a while until you can get around to it.