Sway Bars

[lino]

I just acquired a few things:

Eibach Sway Bar Box (Not the sway bars unfortunately)

and

W124 1988 300E OEM Front and OEM Rear Sway Bars + Bushings

From what I read so far, I understand that my 1989 300ce has a 13mm rear bar and the sedan has a 15mm rear bar. I was wondering if I should consider using the 15mm rear bar to replace the 13mm that I have on my coupe currently. Buying the Sportline Plus sway bars will be a future upgrade. If not, can someone tell me which bushings I have?

Thank You