def 90/110/130 rear anti roll bars?fit rr classic?

having not seen a defender rear antirol bar in the fleash to speak..i need to know which if any would fit the range rover classic...and as want a stiffer than the rrc one which is the thickest dia..?i guess a 130..

not keen on the £230+ from extreme and the bearmach one at 175 +.

thanks