2007 4 cyl locker?

I own 2007 Reg Cab Prerunner 4 cyl. Regretting not getting 4wd but would like to investigate the possibility of a locking differential. I pull a boat, and a locker would be helpful on a boat ramp.

 

You can get the ARB air locker at the link. You'll need a compressor and install everything would total upwards of $2000. But, there's been several here with issues of the ARB leaking in the 8.4" rear.

https://www.justdifferentials.com/Toyota-8-4-ARB-RD129-Air-Locker-p/arbrd129.htm

Perhaps a better route and cheaper would the the Eaton electric locker.

https://www.justdifferentials.com/Eaton-E-Locker-Toyota-8-4-p/eat14216-1.htm