The Tyrrell 025 was a pretty run-of-the-mill F1 car, although as far as automotive technology goes, it was incredibly advanced. The Tyrrell 025 had a carbon fiber body, V-8 engine (though competitors had V-10s) and a double wishbone suspension. It also had a fairly undistinguished racing career, winning just two points in the Monaco Grand Prix in 1997 [source: Racing-reference.info].
This is where you start wondering why a car with an undistinguished racing career is on a list of banned cars. If it wasn't winning, why would race officials be worried about an unfair advantage? This is another banned car that lost racing rights because of safety concerns.
When the Tyrrell 025 was driven in races where the course required a lot of downforce due to curves and turns, the team would put X-wings on the Tyrrell's body near the cockpit. Soon, other teams were doing the same, and all the extra X-wings raised safety concerns when the cars were in the pits — it was just too easy for crew members to get caught up in them. The FIA banned X-wings in 1998 [source: Spurgeon].