[RM7]

I had a WRX, drove STIs, modded, had fun, etc.

The good:

-Fast around a track usually with short ratio gear set for max acceleration. Despite what I mention below, handling doesn't "suck" necessarily, it just reaches limits when pushed earlier than other configurations.
-Turbo and AWD to put power down, good kick of torque at relatively low RPM compared to NA cars.
-Darn near track-ready from the factory, just need roll cage, pads and tires really.
-Does pretty well with mods, WRX/STI are usually good for about 50% more crank HP before needing serious drivetrain mods everywhere. Lots of support and mods available, not crazy expensive like euro stuff either.
-Usually pretty reliable if you don't go crazy with tuning, and then it depends solely on how well you know what you are doing and what is required for your your goal.
-Hatch model is super practical compared to sedan, just the fact that they offer it in the years specified by the OP is a huge bonus to me. The sedan from the same years looks like a haphazard afterthought. Although my favorite is the 2004-2007, I'd go for the 2008 hatch, it's a superior/stiffer chassis. Just having one sedan version with the new STI is disappointing to me, especially with the same engine and power.

The bad:
-Poor weight bias causes understeer followed by snap oversteer, many things can help with this, but it's inherently a flawed chassis, like the porsche 911 (in fact, just the reverse of the 911 turbo). They are kind of backed into a corner, because the engine has to be in front of the front axle to make the AWD function like they want, all the time with power to all the wheels. The low CG of the flat engine is offset by the fact that it's in front of the front axle. You have to push pretty hard to make this your limiting factor, but it's still there. This is one reason why the Evo has nearly always outhandled the STI, much more neutral weight distribution/moment of inertia. You'd think AWD with performance tires would rip, and in some ways it did, but my camaro SS sticks to the road, even in the wet, way better than that subaru ever would. Once it was slightly icy/snowy, ok, out the window, but up until that point, the AWD wasn't really all that. It's a little helpful for accelerating out of turns, but you need the wheel HP to make that happen.
-Poor economy and highway RPMs. Lacking direct injection and with the short ratio transmission, this thing buzzes along at relatively high RPMs and crams fuel down like crazy for cooling when you mash the throttle.
-Drivetrain drag and low whp. The STI dynos around 240hp. Think about that for a little while. A 328 dynos around 240hp as well. The old WRXs were around 170whp, while the 2.5s got around 190, when the more powerful 2009 version came along, it bumped up again to about 210whp or so. These are all pretty low wheel horsepower ratings and they are exactly why the rolling/passing acceleration for these cars are relatively poor. You can get the numbers up with some relatively easy mods of course, but it's just disappointing that Subaru doesn't try to make the cars more competitive with what is being offered out there by other manufacturers....or keeping them from being dusted by an Accord V6 on the highway.
-General lack of technology. Subaru often puts technology on their JDM cars that they never bring over to the US. In the same line as the basic hp/tq numbers, twin scroll turbos, complete forged internals (and not just pistons) and other technologies are often left out of the US market. The absolute worst was in 2008 when Subaru tried to pass off what was known as the "Impreza GT" in Japan as the "WRX" in the US. This wasn't really a WRX and mostly just a basic Impreza with a turbo, complete with wobbly suspension and all sorts of body roll.

The bottom line is that these are mostly good cars and they respond well to tuning, but you have to know what you are doing and use common sense. A good one usually commands a crazy premium price and modded ones are often beat to hell or modded by morons. Still, if you can get your hands on a JDM or built motor for them and pair them up with a decent trans, it can be tons of fun. STI is a good track machine. You can make a WRX into a good track machine with all the parts available. It's disappointing that Subaru hasn't really improved the car significantly. To be competitive the car should be coming with at least 350hp/tq, especially with a 2.5 block. I put 140k on a stage 2 wrx with turbo-back, intercooler, adjustments to wg, ECU, intake, and other stuff that I can't remember now. 280-300hp or so. Only problem I had was a hole in the coolant hose because when I put it back after the timing belt change it was rubbing on a pulley, took me a while to track down why I was smelling coolant, but figured it out and no problems. I will say changing the steering bushings (near when I sold it) was one of the worst auto jobs I've ever done, haha. Just not very accessible.

The only golf that gives the STI a run for it's money is the 292hp AWD version. Otherwise, the STI is on a different planet in terms of handling, track-ability, etc..