Grrrr, foglights!
There are some roads were I think I could do with having more power to my main beams, but I can foresee a problem with fitting more powerful lights... oncoming traffic.
a) Now, say you're driving down a country lane in the dark, and a car comes round the corner ahead. You can usually spot him coming because he is lighting up the hedges and so forth. So, you know to switch to dipped.
b) At other times, especially on clear nights when driving on roads with lots of hills, you won't see him coming until you actually see his headlights. You get a brief period where you dazzle each other a little, and then you both dip... I would think the contours of the countryside mean you are shining mostly above the other car as you come over the peak.
However, if you have much more powerful lights, then in situation a), your lights may be so bright that you don't notice his lighting up of the hedges etc.
In situation b), if you don't see the oncoming car until relatively close, then you will dazzle him a lot. It's bad enough with standard main beams, but generally you can slow down in time to recover before you hit anything! However, with these super-main beams, you would dazzle someone far more severely.
So, rather than just upgrade the bulbs, perhaps you should consider an entirely separate extra set of lights you can switch in and out? Perhaps have them linked to your main beams with a relay, but certainly give yourself control to switch them in and out.
That way you could use them on an unlit motorway, where you need the extra distance to keep your speed up, but on winding country lanes where you only need to see as far as the next corner, you could rely on your standard mainbeam.
If you don't mind doing a bit of modification, you might even be able to fit the extra bulbs in the standard reflectors alongside the standard ones.