This custom LSD Conversion is designed for the OEM Q50 rear 38500-AR61A differential carrier, including Sport, Red Sport, Red Sport 400, Luxe, 2.0, and V6/3.0 models. Select our Q50 Rear Limited Slip Conversion alone to do the "Gear Prep" step on your end, or choose our Q50 Rear LSD Conversion plus Q50 OEM Gears Set"4 Internal OEM differential axle and spider gears" for an easy plug-and-play install. (If this option is available, it will show in the drop-down selection.) There is an option to return your OEM Gears for a Core Gear reimbursement. You must purchase the LSD Conversion plus Gear Set option and request your RMA# for the Core Gear return. This is only available for 14 days after your delivery. The amount of the Core Gear reimbursement depends on market value at the time of the order. This Q50 Rear LSD Conversion Kit is for the new generation Infiniti Q50 2013-present rear open diff and also the Infiniti Q60 2016+ rear open differential AWD/RWD 7-Speed transmissions. Including Jatco: JR710E/JR711E & Nissan RE7R01A/RE7R01B (See extended info for more installation tips) This is not the same R190 Rear as found in the earlier classic Datsun/Nissan R190 differentials and this Q50/Q60 LSD Conversion Kit will not work on one of those R190 differentials. Traction C oncepts Limited Slip Conversion Kit installs into your non-LSD open differential, converting it into a proven and competitive limited slip differential that enhances your traction needs. Our TC Limited Slip 1.5 way LSD will considerably improve handling in daily driven, street/strip warriors, or a full race vehicle. All Traction Concepts products are constructed of only the highest-quality hand selected materials. With over 500,000 miles of vigorous professional performance testing (SCCA, drag, rally, hill climb, ice, rain, etc.), we have been able to fine tune each application through specific heat treating and Rockwell testing to achieve maximum performance and reliability. Each Traction Concepts LSD