Alright having 3 invasions and 1 theory...hopefully I can add some help to your issue.

 

I use the invasion when I need an "pop" off the backend like you describe when im on heavy oil, just as long as its heavy oil.  I see the theory being simply a stronger cell, which is a good thing, when I need a predictable motion controlling the midlane.  I would assume your cell is about as beat up and wore out as mine.  It may be time to replace that cell with a theory, I did and I love it. 

 

either ball will do the trick....if you want a stronger motion but similar to your cell go with the theory....if a totally different ball motion is desired try the invasion...i shot 2289 in my city tourney last year on a heavier shot and pretty much dominated because of the ball being able to handle oil while at the same time snap on the backend. 

 

I think the theory is the safer bet, I have had and heard nothing but good things so far, whereas the invasion has been really good for some and really bad for others, but it is a true tournament oil ball @ oob. 

 

Hope I made some sense there....good luck. 

My Cell is beat up, but remarkably still pretty strong.  It's on it's 2nd drill (didn't like the 1st drill I had on it at all) and I keep it at 4000 for a fresh house shot and it's money until the middle of the 2nd game.  If I could get a similar but stronger motion and more pop on the back with a Theory I'd be happy.

 

How does it compare to a Mutant cell?  Are there any other balls from different companies I should be looking at?