well I just finished everything. realigning the piston in with a piston compression tool I rent at Pepboys... was going to buy a c-clamp, but if they have a tool specifically for this job and I can rent it, why not?
the piston isn't really an issue... the er.. dent part just happens to be at the side where the ring doesn't even touch the pad... so thats a good thing... well when I used the pistol tool it rotated the piston a bit and now the dent part touches the pad about.. but overall I think it'll be fine.
the bad news is, I found out the left front piston boot is damaged. there's a rip in there.. so I'm going to have to get that replaced.. which will cost a bundle. sigh.
what I think I will do is remove that entire caliper with the damaged boot completely and just take it to a shop to have them do it for me.. which will save me some labor cost... and reinstall the caliper myself and bleed the entire system AGAIN.
on another note.. even though there's a small rip in one of the boot, and a dent on one of the piston...
the new system filled with new fluid and new Nissin brake pads performes great.
as always, the best way to learn is through experience.. but its also the most expensive way to learn.
never rush a job, and always have the proper tools before you do a work!