Grim's Rifts SDC/MDC Re-tool

I have always thought the rules on SDC/MDC interactions in Rifts were a bit unbalanced and heavily skewed in the favour of MDC. I of course realize that this is mostly intentional but at times it ungainly and quite frankly power gamey. I believe I have come up with a system that levels the playing field and makes the game a bit more interesting. SDC/MDC Re-tool - There is no conversion rate between the two values either way. So lets get the easy stuff out of the way... SDC to SDC - standard rules apply MDC to MDC - standard rules apply MDC to SDC - standard damage, no conversion. SDC to MDC - When attacking an MDC creature, structure or vehicle with an SDC weapon or attack, use the following system. - Light rated MDC targets have an AR 12 against SDC attacks and take half damage if the AR is not beaten and full damage if the attack roll is over the AR. - Medium rated MDC targets have an AR 15  against SDC attacks and take no damage if the attack does not roll above the AR and half damage if the attack exceeds the AR. - Heavy rated MDC targets cannot be effected by SDC attacks. These are the basics of the rules and I would appreciate feedback and suggestions on how to tweak them. Once I am happy with them I plan on running a Rifts game using the polished product. 

The whole point of the MDC/SDC trade off was that it was unbalanced, that was one of the fundamental draws of the game.  Just look at what MDC was supposed to represent in the original SDC/MDC example in the Rifts Main Book (p.38); a modern  TANK.   Those are pretty light rated by Rifts standards, but was still demonstrated as impervious to everything short of a bazooka- because one of the main selling points of Rifts was playing characters that were capable of fighting well above the capabilities of modern forces (the main turret of said tank only did 4 MD, to put it in perspective).  Leveling the playing field loses the entire point and purpose of the Mega-Damage concept, especially when all you do is nerf armor while keeping weaponry untouched. Try taking a look at Savage Rifts ; they managed to lower the crazy mega-number game while still keeping the concept intact.

I think it probably slows the combat down unnecessarily. Combat is already pretty intense and now you’d add in another consideration, is this light or heavy MDC target. And why would anyone use SDC weapons? Even if you give them a chance to hurt MDC targets, everyone will still try to get MDC attacks to make sure they do damage. Some classes like Burster are hamstrung because they’re old and pre power creep, and thus have a bunch of SDC abilities they never use, but even for them it would still be more efficient to just use MDC.  MDC to SDC targets is standard damage? So hundreds of points or just the raw number in SDC?

If your group wants to use the SDC/MDC conversion you suggested that is perfectly fine.  I find that combat is already pretty involved and adding complexity tends to slow it down further at least in my games.  For my part I have gone the other way trying to consolidate and reduce complexity. For exanple, I compressed the skill list in RIFTs, unless the players  actually wanted all the different subtypes.  Made the game move faster. I mean if we're playing Palladium, there's going to be disorganized unbalanced inconsistent crunch...that's how KS rolls and he had emphatically said several times he won't ever change.  :)