I have a completely stock magcharger and would like any recommendations on a first mod. I have to buy a new battery and am willing to do new reflector, socket, glass etc if it is really worth the $100??? it may cost.
Even stock Magcharger is still a good flashlight and if you like it there are some posibilities (some of them you mentioned in your post), but the easiest way to greatly improve output and still have original runtime, is to get drop-in like Terralux MiniStar31 MR or MR-Ex.
First things first get rid of that horrible plastic lens (if it has one) and get a glass one.
The magcharger already has a GLASS reflector altough a UCL or borofloat might have better light tranmission properties..so the magcharger window doesn't really need any upgrading if you don't want to..the reflector is also metal(partly metal) because even the stock 10W halogen blub in the magcharger would melt plastic lenses and plastic reflectors..if you want to upgrade to LED,i think normal mags are better platforms for modding but if you want the magcharger..you can go the hotwire route,ie use a different blub (for example WA 1160 which is just a matter of buying and dropping in the bulb) or go for the MC85..then u'll have to consider putting heat shields in between the bulb and the plactic socket or upgrade the socket itself to ceramic( i think member fivemega still has the ceramic slug for the MC) can't remembr if they have a regulated switch..plus you'll need more voltage and current( search member modocod for battery adaptors)do a search on "magcharger mods" or "MC 85" and you should get tons of results relating to the magcharger. all depends on bugdet and want/goal..