My experience with Mintex is that 1155 need a few good stops to get the heat into them before they work. From stone cold in the morning they are useless. Mintex 1144 work better from the off but dont offer as much fade resistance as 1155 on track. Neither of these pads will ever fade on the road. Both squeele badly and produce lots of brake dust but they are reasonably cheap.
Pagid make some really good pads for the Impreza and are worth pricing. The Ferodo DS 2500 is accepted as the best pad for the Impreza but is also one of the most expensive.
I put motor factor standard chepo pads on my 280 bhp MY 03 WRX before I sold it in 2007. For the kind of driving you describe they were fine, just so long as you dont expect them to hold up to any kind of hard driving. As always its horses for courses The more horses you use the better the pad you'll need.
Frawls