Yeah, Megan Racing definately has some pretty reasonable price. I have talked to some 1st gen VR4 owners who used the downpipe and for the most part they loved it. I know one guy who bought it said it ended up cracking after a year or two but just fixed it by taking it to an exhaust shop and having a flex section welded in. Which even in that case, they are still spending less than the price of pretty much any other downpipe. The one place I do try to avoid that specializes in 3S's is 3SX though. My God, bring out the big wallet!
Back to the STi though. Are you planning on taking it to the track any time soon? I would imagine with a good run you should be able to hit a high 12 with those mods if you can launch the awd it properly.