Engine, 3.6L V6, direct injection (SIDI), DOHC, variable valve timing (VVT), 308 hp at 6800 rpm, 265 lb-ft at 2400 rpm

321 hp; the 3.6L models (1SN to 1ST)

The 2014 Coupe guide rates it at 318 hp and 275 lb-ft; CTS Coupe, Performance, Premium (RWD and AWD): S; CTS-V Coupe: not available

Wikipedia's High Feature engine article gives the SRX application years (2012 to 2016, clipped here to 2012 to 2015, the 2016 row being factory-cited), and Wikipedia's SRX article names the code LFX in its infobox and says the 3.6L arrived in 2012; the Chevrolet Equinox (2015 fleet order guide) and GMC Terrain (2016 fleet order guide) list the same code for their 3.6L V6, which corroborates the code only; no factory page in the archive for these years

all trims: S, FWD and AWD; GM's 2016 SRX order guide (GM Authority's copy, published September 18, 2015)

304 hp; Wikipedia's engine table for the XTS names LFX as the 3.6L V6 and dates it 2013–2019 (2013 and 2019 come from that table); GM's 2014 Car and Truck Guide lists a 3.6L SIDI DOHC V6 VVT at 304 hp for the XTS without printing the code; sibling: the Chevrolet Impala (also Epsilon II) prints LFX as its 3.6L V6 in its 2014 fleet order guide, a corroboration of the code only and not an XTS source; single-source: the XTS tie is Wikipedia alone