Re: MSG Ignition Stuff
MonoSodiumGlutamate won't do your Jeep engine any good.
Couldn't resist(even though I can't spell either). Do a search on the TR upgrade. You will get a nights worth of reading, and learn more about the MSD unit and the ignition systems of Jeeps, TFI(Ford), and HEI(Chevy) than you will want to know.
Do the search, do the reading, it's all already here.
But to actually answer your question, yes the MSD is worth the money. Do it with the TR upgrade and look into the Nutter Bypass for your 258 and you will have an almost rock solid engine. Swap out that Carter BBD for a Motorcraft 2100 and most all of your 258's stock problems will be solved.
In fact if you upgrade the iginition to TR and MSD, swap BBD for 2100, and do Nutter Bypass on computer it should cost less than $350, not bad if you ask me.
llll '90 YJ, NV4500, XD9000i, 35" MT/R, Snorkle, 4.5" RE lift, Tera Revolvers, etc. etc.