DSMs have a bad wrap for being unreliable. My Talon was very reliable for me. It was because I took care of it engine wise. I just never washed it and let serious dirt build up after several off road rally fun days. I washed the car once since I bought it. I wish I had washed it more because it turned out to be a problem for me, but still never had serious engine issues. I did wash the engine bay often though!
As long as you take care of the car, play it smart, you can upgrade it with minor issues. DSMs are very affordable cars with a reputation of going fast for cheap. So who buys them? 16 year olds that just get their license and know nothing about cars, but want to have the fastest car to show off for their high school buddies. They see the videos of Shepard, Magnus, etc. and think they can do it right out of the box. They destroy their car quick by modding too much, and by not keeping maintenance up. Much like what would happen with any car.
When I first got my license I bought my Talon for the same reason those kids did. Many people I went to school with also bought first gen DSMs. By the end of my senior year i was the only one with a drivable DSM. i was the only one willing to go home after football/lacrosse practice and work on the car instead of going to my girlfriends house to get laid, or get hammered w/friends because it's the cool thing to do. I made time for my girlfriend (who I am still with BTW) and to hang out with friends but I had my priorities. School work and Car running were at the top of my list.
Then to make matters worse (and I have seen a lot of this) when the kids sell their "unreliable broken down DSM" another fresh driver snatches it up thinking he will fix it up, and they never do, for the same reasons listed above. Then it ends up in the classifieds again and gains more of a reputation as an "unreliable car." They never even drove it, it sat in their yard!
In turn they destroy the reputation of, what I feel to be, a great car. It's sad that kids that know absolutely nothing have that kind of power, but it's true. Rumors period. Start one lie and it spreads.
If you buy a broken down car, expect work, obviously! If you don't take care of your car, it will break down on you, obviously...
Spend some time on the DSM forums. You'll see that all the hard working owners that take care of their DSM will tell you that the car was actually one of the more reliable cars they've owned.