I personaly only know 1 person who has Intrax springs on a Toyota Echo but hes only had the car a few months.
Other than that, all my friends run Eibach and none of them have complained about a problem they all love them. They have a good host of cars, Sunfire, MX-6, MX-3, Civics, Golfs, none of them have problems. I also had a set of Ford Motorsport springs, which were supposedly made by Eibach on my T-bird. I'm gonna go Eibach I'd suggest the same.
Good luck with the Intrax though
Hope to see your pics...see if you can get a stock vs. lowered Protege side by side pic!