As far as fitment is concerned, these will bolt right in. Our foresters (SG) will fit 02-07 WRX and 04 STi struts. You may want to find out what car they came from, just to be sure they truly are 02-07 WRX fitment. If they were made for 05 STi's, you are in for a not-so-fun fab job.
I had never heard of Zeal Function so I did a little digging through the Impreza forums and the general consensus for Zeal Function coilovers are that they work fantastic on the track, but still work quite well for daily drivers. The spring rate is much higher when compared to other coilovers in the same price range like HKS.
I don't know how much you are looking to pay but the cheapest I found on ebay were like $1000+. Brand new you are looking at over $2000-$3000 (ish). Some people were saying they are overpriced, but they didn't offer anything to back up said claim. So depending on the price, you may have quite the bargain. Hope this helps mate!