I am a paid member of the visualizer. Its a site that gives you a graphical and mathmatical equivilent of your penis compared to other penises. Here is the cubic centameter volume for dicks:
small dick average 104
average dick 193
mr. 8x6 348
mr. 9x7 541
mr. 10x7.7 717
The problem with getting bigger is the expontial volume. Two extra inches of length and girth on top of your 8x6 doesn't seems that big of deal, However, Its over twice the mass of Mr. 8x6! Here is a forum post by a guy around 10x8. He can no longer have sex.
True Monstercock PUMPED
Life is about sacrifices. If you want lots of hard great sex, 5x4 to 7.5x5.5 with high EQ is the range you want to be. Those sizes can nail their girl day after day. Above 7 x5 you get more wow visual factor. But as you go up in size you are required to go softer, slower, lube and the girls will need time off to recover. (sometimes days)
The stories about guys with 9x6.5 having 3 somes are probably true, but not what you expect. Its not like porn where he is banging away at two amazing looking sexual goddesses. Most girls are average looking. And many times annoying after your libido goes down. Plus you have to be extra carefull with the new girl. Think turtle sex.
Your size is about what is important to you.