I believe the difference between them is the transmission. Someone correct me if I'm wrong.
Here is the page that shows the different 1.8L trims. It looks like the transmission is the only difference:
1LS
MSRP¹: Starting at
$13,735
•ECOTEC® 1.8L with 5-speed manual transmission
•OnStar®, 6 months of Directions & Connections® Plan(2)
•Remote Keyless Entry
•StabiliTrak® Electronic Stability Control System with rollover sensor and Traction Control
•15-inch aluminum wheels
•Ten standard air bags(6)
2LS
MSRP¹: Starting at
$14,805
•ECOTEC® 1.8L with 6-speed automatic transmission
•OnStar®, 6 months of Directions & Connections® Plan(2)
•Remote Keyless Entry
•StabiliTrak® Electronic Stability Control System with rollover sensor and Traction Control
•15-inch aluminum wheels
•Ten standard air bags(6)
1LT
MSRP¹: Starting at
$14,935
•ECOTEC® 1.8L with 5-speed manual transmission
•SiriusXM™ Satellite Radio(3) with 3 trial months
•Power Windows with driver Express-Up and Down and anti-pinch feature
•StabiliTrak® Electronic Stability Control System with rollover sensor and Traction Control
•15-inch aluminum wheels
•Ten standard air bags(6)
2LT
MSRP¹: Starting at
$16,005
•ECOTEC® 1.8L with 6-speed automatic transmission
•SiriusXM™ Satellite Radio(3) with 3 trial months
•Power Windows with driver Express-Up and Down and anti-pinch feature
•StabiliTrak® Electronic Stability Control System with rollover sensor and Traction Control
•15-inch aluminum wheels
•Ten standard air bags(6)
1LZ
MSRP¹: Starting at
$16,535
•ECOTEC® 1.8L with 5-speed manual transmission
•Bluetooth®(4) wireless technology for select phones
•AM/FM stereo with CD player and MP3 playback, equalizer, auxiliary input jack USB port(5) and Bluetooth® Audio(4) Streaming for select compatible audio devices
•StabiliTrak® Electronic Stability Control System with rollover sensor and Traction Control
•17-inch aluminum wheels
•Ten standard air bags(6)
•Leather wrapped streering wheel with cruise control and audio control buttons
•Fog Lamps
2LZ
MSRP¹: Starting at
$17,795
•ECOTEC® 1.8L with 6-speed automatic transmission
•Bluetooth®(4) wireless technology for select phones
•AM/FM stereo with CD player and MP3 playback, equalizer, auxiliary input jack USB port(5) and Bluetooth® Audio(4) Streaming for select compatible audio devices
•StabiliTrak® Electronic Stability Control System with rollover sensor and Traction Control
•17-inch aluminum wheels
•Ten standard air bags(6)
•Leather wrapped streering wheel with cruise control and audio control buttons
•Fog Lamps
.
I imagine the trims for the 1.4L will look the same.