more spark plug questions

#1
what is the difference between a NGK bm6a and NGK bm7a?
#2
what is the difference between a NGK bpm6a and NGK bpm7a?
#3
what is the difference between the NGK bm6a/bm7a and the bpm6a/bpm7a?

thanks very much as i really appraiate ur help

Well I can tell you this much the 6's are a hotter plug than the 7's. I've never used the bpm pluggs so I can't really say.

thanks for your replie....
so wich would you say is better? the 6 or 7? maybe the 6 becuase it is hotter? or is it not good to be hott?
thanks very much for your time

anyone else got answers?

looks like the only difference is the removable terminal that you can unscrew Im also thinking this plug has a little more total height from the base to the terminal like 10-15mm more

BM6A
14mm Thread, 9.5mm (3/8") Reach, 3/4" (19mm) Hex Size, Gasket Seat, Non-Resistor, Solid Terminal, Compact Small Engine Plug, .027" (0.7mm) Gap, Heat Range 6

BPM6A
14mm Thread, 9.5mm (3/8") Reach, 3/4" (19mm) Hex Size, Gasket Seat, Non-Resistor, Removable Terminal, JIS Height, Projected Tip, Compact Plug, .027" (0.7mm) Gap, Heat Range 6

whats the best one for a stock replacement ? i want the same size