I think the thing to remember is the more you upgrade the performance the more likely you are to break a related part, limit the upgrades to reliability upgrades (new fuel pump, new injectors, new turbo with better cooling and oiling than older ones, latest chip burned for the gas you can buy locally with a conservative timing and other options, better brakes, better suspension, etc. Also even for a DD things like powerloggers and scanmasters are not a bad idea, even though you're not "pushing the envelope" keeping an eye on things with data logging is never a bad idea (unless you're playing with the scanmaster or your laptop at 80 mph on the morning freeway ride).
No one ever broke their car because they put bigger brakes on their car, or a new fuel pump, or upgraded sway bars, control arms, etc. (ok I'm sure someone has but you get my meaning) but add a set of injectors, an adjustable wastegate and 18 pounds of boost later and there's all sorts of stories, add another $500 for alky and bump the boost to 20++ and you can't swing a dead squirrel without hitting a thread about something breaking.
And then there's guys running every bolt on and upgrade imaginable and have been for 100K miles, just saying the law of averages says keep the performance upgrades mild and the handling/braking/support system upgrades to the tough stuff and you can drive the snot out of these, or most any, old car.
So far in a year of driving mine (granted I drive very little, barely 2000 miles this year) the only time I was semi stranded is my own fault, I replaced my injectors and when I put the FPR back on I cinched the rubber gasket and when it heated up my FPR turned into the OPPOSITE of a fire suppression sprinkler
eek
10 minutes after my wife shows up with a roll of paper towels, my trusty 100 and something piece Craftsman kit and the spare FPR I had on my desk (with 2 gaskets on it) I was back on the road (after mopping up the gas on the intake and valve covers and just all over really)..
