Gli has a 1300cc engine that produces 84 HP.
While the Altis 1.6 comes with a 1600cc 120 HP.
That definitely puts things straight. That's all there is to it, but I'll tell you what mate. These cars aren't under powered even if they're 1300 like the swift. It depends on the technology they use in their engines. The Mazda RX8 for example comes with a 1300cc engine, and it's a proper sports car. So, yeah, you can't say it's under powered. Yes, it is as COMPARED to the Altis 1.6, but that works, y'know?