The SMY dual gauge pod for 2002-07 WRX/STI cars was engineered to fit like a factory part. Details like internal reinforcement ribs, and posts that accept the factory spring clips, mean it installs and fits just like a stock part, without unsightly warping or sagging. Fits two 52mm gauges. Note that mounting depth is limited to just over 2", so extra deep gauges are not going to fit, or will stick out a little. If your gauge has long mounting posts on the back side, you might need to trim those off.
Fits left-hand-drive cars (like in the U.S. and most of the rest of the world) perfectly. Fits right-hand-drive cars 95% perfectly -- there will be a small gap on the right side, but it's not bad.
Fits all 2002-2007 Impreza, WRX, and STI.