sound lads.Johnny,i think the only difference is that the bottom bushing is wider on the IRS ones,i could be wrong,but i think it would work if you put a spacer either side.Kieran,theres not a lot different about these height wise to a standard shock-they are slightly shorter when fully extended,and can compress slightly more,i think,but the main difference is that you can soften or stiffen them very easily-but if ye want them no bother-cheers