I did an experiment this past year.
I started noticing a while back that cycles with one drug would be going fine, then when I would add something else, I'd get sides (like high BP). I always blamed the drug that I added for the side effects, before realizing that at the times I ran that drug solo, I didn't have those sides.
For example. Running test alone with no issues. I added tren, started getting sensitive nips, psychological changes, higher BP, etc.
So this year I ran tren solo. I started at 25mg per day. I had no sides. I bumped to 50mg per day, had no sides. bumped to 75mg per day, minimal sides. 100mg per day, still very tolerable, barely any changes in BP, no gyno issues.
For the last week of that cycle, I was able to take 200mg per day.
I only ran it that way for about ten days because it was getting to the point where it was just time to wrap things up. It was only when I was at 200mg per day that BP went up, but still lower than some of the BP numbers I see reported on heavy cycles on these forums.
I ran some other cycles without test this year, and they went pretty well too. I guess what I am trying to say is, my side effects are MUCH worse when stacking certain drugs than when taking high doses of one drug by itself.
I may spend 2012 playing with higher doses of one drug, then just switching compounds as time goes on.
Tren isn't the evil side effect drug that I thought it was. It only had harsh sides when I ran it with stuff like test and d-bol.
I still think stacking has it merits. I just think more time has to be spent deciding what drugs to combine. A non aromatizing oral like T-bol or var with the tren for example.