TL-3 and M3 LO have similar bulb with almost same wattage.I’ll tell you this. my streamlight TL3 is just as bright and throws just as far as my surefire M3 and damn near as far as my M4! It’s crazy.
M3 has option for higher output bulb with shorter run time and bulbs are shock proof with pre focused beam, TL-3 does not have HO bulb unless you go aftermarket 1499 or even 1794 with focusable beam.
M3 and M4 possible to bore out for 18mm rechargeable option but TL-3 can be used with 16 or 17mm batteries only.
Extension tubes available for M3, M4 to use more or longer cells but there is no such an option for TL-3 unless you go aftermarket body.