Want to upgrade my computer for this game, need some advice.

[Judge_Xero]

My experience on lagging plumes in titan was from a laptop with 750m, with shadows at medium or max the plumes would cause the game to lag really badly.

If you tried it on the FX 8350 would you still say that the overall perfromance of the game wouldn't be better with a better GPU? Also the OP asked for the computer to be able to run it on max. The 660 isn't going to make it with max settings.

Well, before my current Rig I had an Intel i5 4670k while using the AMD R9 290. Going from the FX 8350 at Max Settings to the i5 4670k at Max setting there was a noticeable difference in congested areas, but comparing the difference while having the game reduce the number of players rendered, there was no difference, visibly.

Even with the lesser Core2 Quad and the GTX 550ti, if I played with Objects Rendered at Medium then it could handle 20-30 FPS at Maximum Eye candy.

----------------------------------------------

I suppose if the OP got a GTX 970 while keeping the FX 6300 - Overclock it and reduced the number of Rendered Objects then they would see more performance than what the GTX 660 gives. It would just be subjective on whether there is a visible difference, since it would probably be a case of:

45-60 FPS VS 50-90 FPS