Stock for stock I really think the r series runs circles around the 8.8.
now built thats different but hell your talking 1500.00 plus to do one right. Just saying
Sorry there is no chance of an R200 being better for this purpose than an 8.8.
Also, the Detroit Truetrac is not a locker, it is a Torsen style diff. It is very consistent and is silent in operation. It it one of the best mods I have done to the car.
A $219 8.8 Ford OEM carbon clutch LSD is great for 90% of people that drive on the street, even people that run 600+ HP. A Detroit TrueTrac is $450 if you want a bulletproof Torsen style diff for corner carving or racing. There are also other diff options like the T2R, Wavetrac, OS Giken etc. that range from $600 to $1000.
You can fully rebuild the 8.8 for $80, and any gear ratio you could ever want is available.