Back in the early 70's I used to do a lot of shocks on the early Mcphersons before they went to the OEM cartridge style shocks. Yank out the guts, dump out the oil, slide in a new set of Monro gas cartridges and crank down the new spanner nuts - "250 dollars, thank you very much." There's lots of available travel on this type of strut assy. I've never had occasin to slam one yet, but I'm sure it can be done. There really isn't much labor involved in tearing one down to find out. A new set of springs would be a cheap education if it doesn't work well. If you cut them, cut 'em on the bottom. That is where the spring end indexes into the pocket. As I recall, the top side that fits the upper spring bucket is flat with a poly cushion. I'd get a little more info. though, before I tore it up.. Mcpherson frontends have been around for a long time now. There's bound to be sombody out there who's 'slam smart' on the subject.