Not sure what you don't trust about any/all higher-wattage bulbs. Sure, there's a ton of junk on the market and yes, you can't just throw in giant big-watt bulbs, but the 70/65w Osram is a terrific upgrade over Xtreme Power and is compatible with most stock wiring, particularly that equipped with relays -- and without a dangerous level of glare in headlights like yours, as long as they're aimed correctly.
This advice does not apply across all headlamps, but specifically to certain types, including large well-focused H4s like yours. The H4 system has very good inherent glare control because of the low beam filament shield, but that same shield means you only get to use 55% of your total lens and reflector area to gather and focus light. The tradeoff is sharp beam focus, but low flux within the beam. On the other end of the scale you have something like an HB1 (9004), HB5 (9007) or H13 bulb, which has no filament shield, and while virtually 100% of the reflector and lens area is used to collect and direct light for low beam (so there's more light within the beam than with H4), that same 100% of the reflector and lens is also used for high beam, so focus is always a compromise and there's no inherent glare control in the system.
An ordinary H4 60/55w bulb produces 1000 lumens on low beam at 13.2v. The 70/65w H4 produces 1350 lumens on low beam at 13.2v. An HB5 or H13 produces about 1200 lumens on low beam at 13.2v. So if you put a 70/65w H4 in place of a 60/55w H4, you have 35% more light, or 1.35 times the baseline value. We still have the efficiency disadvantage of using only 55% of the reflector/lens to collect light, so multiply the 1.35 times 0.55 and you get 0.7425. Multiply that times the output of the new bulb and get 1002 lumens. Now you're within a parking lamp intensity's worth of range of the available light of an HB5 or H13. So what you have done is kept the inherently sharp focus and good glare control of your lamps, while boosting the light level within the beam to that available from more efficient but less well focused systems.
It is worth noting that this is essentially what the Brits did at one point before just adopting the European standard (in which the 60/55w power of the H4 was and is standardized). The Brits had some of the same objections at that time back in the '70s that US regulators still presently have to the European headlamp standard. The British headlight industry for a time produced sealed-beam halogen headlamps with 70/65w H4-type internal bulbs and the English optical prescription that was a questionably-modified European beam pattern, flopped horizontally for British left-side traffic. England's reputation for mediocre vehicle electrics aside, those were not bad headlamps. Eventually the Brits just went ahead and adopted the European standard altogether, unmodified, and those nonstandard-wattage lights went away. But even if their optical philosophy was kind of screwy and leading them down a blind alley, so to speak, the idea/principle was completely sound.
