There has been a big thread on RS25.com for a bit about questions for a bar to connect the rear upper seat belt mounts to create less body flex and roll, due to the lack of back deck reinforcing like the sedans have. Im transferring what I did here for everyone to see.
After spending over 2 hours looking for a stock threaded mounting point behind the C and D pillar trim, that is out of the seat head rest and skull splitting zone
I came to the conclusion that there is none. So I welded in a plate with a threaded mount on the D pillar that was the same height as the upper seat belt mount. Then I went about fabing up connecting bars to join the C and D pillars together. I made then out of 3/4" square tube and 1/8" x 3/4" plate. The C-D connecting bars where made about 1/8" short to create a strengthening load between the two pillars when tightened. Stock "crapy ebay
" lower strut tower bar mounts where used for the lower bar mounts. The bars and turnbuckles are made of 3/4" 13 gauge tube with left and right hand threaded pipe ends welded in. All in all the total for the project cost around $100 with out powder coating. This has made a HUGE!! difference in how the rear end of the wagon handles on hard cornering. And I have BC coilovers with 17x8 rims with 225/45 tires.
The basic parts list of what is needed.
3'x3/4" steel tubes
3'x3/4"x1/8" steel plate
3'x3/4" square steel tube
2" long 3/8"-24 bolts that the hex heads where cut off of to make R/H studs for the turnbuckle to bar connection.
7/16 grade 5 nuts ....or same thread pattern as the Automotive Studs
.......2 nuts and bolts for the welded mounting plates ( I think they where 7/16 as well
......I searched on line for a few hours to find the stuff as cheep as this place had it
3/8-24 RH Weld-In Bung $24.00
3/8-24 LH Weld-In Bung $8.00
3/8 x 3/8-24 Economy Male RH Rod End ( also known as Heim Joints
3/8 x 3/8-24 Economy Male LH Rod End ( also known as Heim Joints
Quick Disconnect are normal Mt Bike seat clamps ( ebay $4 each ) with 3/8" OD to 1/4" ID bushings from Lowes
.....regular bolts could be used
Tractor Supply/Home Depot/Lowes/Sears Hardware ect...
This part is key, its called a Automotive Threaded Stud. You will need 2 of them for the upper seat belt mounts. Pictured below is the thread size you will need for the upper seat belt mount and then just find the corresponding nuts x4
for the other end of the stud. You can do it with out them but, with only bolts the seat belts will not retract due to the bolts pinching the belt guides against the C pillars.....They looks like this from Tractor Supply and are loose in the hardware draws at other stores.