weighting a 2006 sanger v215

i just bought a sanger v215 and am picking it up on friday. i was wondering what is the best way to get the most weight? it comes with two hard tanks in the rear and a bag in the front that equals a total of 700lbs. the dealer said for 800.00 i could get two bags in the rear to replace the hard tanks and the total would be 1000lbs is it worth it or should i put in my own bags later and get even more weight? thanks for the help