Grand Rapids Technologies has expanded its EFIS lineup with the introduction of the Sport SX. Until recently, the company’s EFIS lineup was neatly divided between the Horizon HX, which includes synthetic vision, and the Sport models, which could not be fitted with SV. The key point is that the HX required an external AHRS module, while the Sport EFIS carried its AHRS equipment inside the main display box.Citing the need to upgrade processors in the Sport, GRT elected to add SV as an option to the Sport, now calling it the Sport SX. This new model uses the same screen and bezel arrangement as the Horizon HX, so either the 6.5-inch-diagonal or 8.4-inch-diagonal screen sizes are available. The Sport SX retains the HXs twin knobs and five bezel pushbuttons.Virtually all the features of the Horizon HX are either standard or available on the $3000 Sport SX-and its this parsing of the features that allows GRT to keep the SXs price lower than the standard HX. For example, the HX has standard synthetic vision, which is a $1200 upgrade on the Sport SX. The HX includes an ARINC 429 data interface card, which is $475, plus an additional $500 if you want to enable the Sport SXs vertical autopilot command features (using the ARINC 429 data output). An external GPS is a $400 option, while a WxWorx XM Weather module is a $950 option. The Sport SX also does not support analog inputs or discrete outputs, and has five serial in/out ports versus the Horizon HXs eight.Still, there are considerable cost savings. Comparably configured, the Sport SX (with all the most desirable options) runs $5175, while the Horizon HX runs $7000 with a single external AHRS module. More information on the GRT Sport SX can be found at the company’s web site.