[Comartemis]

Oh? is that Why, in A's, Nanoha couldn't do a regular Divind Buster and had to both make a barrel shot, and then a barely controled spell that split? Ok... O.o

I'm not sure I understand the question, but what Nanoha used against the BoD was an Excelion Buster with Force Burst and Barrel Shot tacked on to it, not a plain old Excelion Buster (plus Blaster 1) like she used against Deici on the Cradle.

Zest was a failed Experiment, but that doesn't change the Fact he couldn't use a powerful spell because of the stress it inflicted on its body. ^^ So there *is* a stress.

All spells have a stress on the linker core, the question is can the mage handle that stress and still function without a problem (most of the lesser spells you see mages use) or will it tax them to their limits (like Full Drives and "Ultimate Techniques" like Starlight Breaker)? Zest couldn't handle spells he probably had no problem using in his first life because his resurrected body was weaker than it originally was.

Let me make one thing absoutely clear here; when I talk about overboosted spells, I'm not talking about spells boosted beyond the mage's ability to control. I'm talking about spells with more power than they were originally designed to make use of. Picture how Naruto always makes hundreds of clones of himself when most ninja can only make two or three. Same concept goes for mages; I'm envisioning Hayate using an S-rank spell but boosting it into the SS-rank because of her control issues, not boosting a SS-rank spell into the SSS-range. Boosting a spell beyond your linker core's ability to power is going to cause problems no matter who you are or how high your mage rank is.

Magic isn't KI.

Same difference as far as boosting the body is concerned. The two forces are similar enough in their usage that I've even seen an idea proposed a while back (when I was still just getting started on the Nanoha/Negima crossover) that Belkans are already using ki in addition to their magic, which is what makes their melee spells so strong.

Magic is *harmful* in too great quantity. It said so in the show. Please, do not contradict the show.

Where in the show has it said that too much magic is harmful to the body? All I know of to that effect is that overstressing your linker core by using more magic than it can handle is dangerous, but I've never heard anything to the effect that your body can only take so many boosting spells being cast on it.