There are many things wrong with what you are doing and what you have self diagnosed.
First, 0w-30 and 5w-30 are the same weight oil. Modifiers in the oil cause it to flow easier with the 0w than with the 5w when the engine is cold. If anything, you are hurting your engine by putting the 5w oil, than by using the 0w, because most engine wear occurs at startup of the engine. Since the 5w won't flow as quickly as the 0w would, you are keeping the engine without oil flow longer, causing more wear. No matter what else you do, go back to using the oil which is recommended for your vehicle. If that means 0w-30, then use it.
Second, while you say you are running only 10k per oil change, most vehicles recommend changing oil about every 5,000km or 3 months which ever comes first. You are basically doubling the oil change interval which adds to oil breakdown and causes more wear on your engine.
Third, 1L or oil per 10k is not a lot of oil to be using, especially considering what you've suggested in your question. More than likely in your case, your car is leaking more oil than it's consuming. (Check the fifth thing below.)
Fourth, most manufacturers have two different oil change intervals. One being for normal use and the other for severe use. Considering what you've suggested about "... I drove the car at the limit sometimes, maybe more than needed, like revving the engine to the redline ..." you are definitely using it in the "severe" use range. There is nothing inherently wrong with using your car in any manner you'd like, but if you're going to be taxing your vehicle, make sure you are treating it well in return.
Fifth, check the inside of the tail pipe for soot. Take your finger and rub it. If the soot which is there comes back greasy feeling, then your engine is burning oil. This would be an indication of oil going out the tail pipe and bad rings which would be causing it. If it's just a little black, then it shouldn't be a big deal. The engine may need a tune up.
Sixth, park your car on a clean piece of concrete (in the driveway works well). In the morning, pull your vehicle back and check for oil spots where it was parked. If you don't find any, that doesn't mean much. If you do find some spots of oil, you know you are leaking a little bit. Lift the hood and check around the engine (on, under, around ... be thorough). You are looking for any dirt buildup on the engine or anything which looks like leaking oil. Look around the valve cover (typical leak spot). Check your accessories for oil or grime buildup. Any of these would indicate you are losing oil through leakage and not through burning the oil.
As an aside, if you haven't done it yet, get the timing belt changed. If this has never been done, you are risking having to get a new engine regardless of if it's burning oil. If the belt should break or slip, your engine will encounter piston to valve contact, destroying at the very least the valves, if bad enough, could require an entire engine to fix.
