lets face it your selling the game dirt cheep ( well unless they are in china lol .
anyway I can say for sure a good add on i would pay again for .
Say you added in a FULL texture modder Simplefiled - so you choose what lot to mod then the add in program would open the lot to be repainted ALL in game saving the aggravation of saving and importing correctly .
Again this was done with other games . A add in like this would be worth another 5 - 8 $ as I for one know the amount of programming required to do it .
Or other add ins that could be payed for . Now your a honest guy and i like that not a greedy bone in you .
But what i am talking about would be enough that even a honest guy would be ok with saying hey its worth 5 $ for this alone . Heck darn turbo bots are worth the 4 $ by them selfs lol