This AutoMeter WRX and STi dual pillar gauge pod from Auto Meter is an easy way to add two 52mm gauges to your interior. This gauge pod only covers a portion of the stock pillar.

Auto Meter pods are installed over your current factory a-pillar and are held into place by a few plastic pins inserted into hole you drill in the stock a-pillar. Although this doesn't sound great they fit very well and look excellent when installed.