[Kelly Pedersen]

The first question to ask is, "Which lasers? And which tanks?". Choosing the exact technology will help us determine effectiveness. For example, say it's a modern TL 8 military you're talking about, and a TL 11 alien force, one that uses X-ray lasers for their main beam weapons. If the aliens are all fielding X-ray dino lasers (8d, armor divisor 5) as their primary weapons, they'll be at least potentially effective against a TL 8 main battle tank (which has 1155 DR on the front, but only 165 DR against all other directions). The dino laser is doing slightly less damage on average than will penetrate the sides DR (avg. damage of 28 vs. the tank's DR, after divisor, of 33), but only slightly less. Several alien soldiers can probably whittle down the tank.

But that's just assuming the aliens have laser rifles, which, if they're expected to go up against things like tanks, is probably not the case. Rifles are designed to be carried by someone with human strength, basically unaugmented, and used against other infantry. If the aliens are regularly taking on bigger prey, and have some technology to make themselves stronger, they'll use bigger weapons. For example, with the sort of strength boosts available at TL 11 (battlesuits and similar stuff), carrying a semi-portable x-ray laser around seems considerably more practical. At 12d (5), that's now doing an average of 9 damage to the tank per shot that hits, and with the tank's large SM and the laser's high Acc and RoF and low Rcl, that's actually quite a lot of shots potentially hitting for every attack roll. The main battle tank's 176 HP may vanish faster than you'd think.

As a more general piece of advice, though, I'd also point out that you don't have to use published stats for any equipment if you don't think they're accurately representing the setting. This is all in aid of a Dragonball game, right? In that setting, it seems to me that military hardware is mostly there to show how incredible the protagonists are when they blow them up, not to be a serious challenge, and to show off how badass the alien tech is when it makes mincemeat of it. Consider simply dividing all DR and HP on things like tanks by some number, like 10. If a main battle tank has 116 DR on its front and 17 DR everywhere else, and 18 HP, it'll blow up very satisfactorily after one or two hits from either a strong ki user or an alien firing a laser blast. And meanwhile, to make your aliens or ki users competitive, you don't have to make them so powerful that there's a huge gulf between them and the next lower tiers. Just establish at the start that the tanks and other stuff having lowered resistance to damage is just a genre conceit, and ask the players not to try weird tricks with it.