I have to agree with Robert Smith on the Thunder Flash Pro.  I needed a ball for a very light volume top hat pattern with a distance of 28'.  I needed a ball where I can open the lane up on this shot and not over react on the back.  With this in mind, I layed out my Thunder Flash pro as follows.  I am right handed.  The ball was sanded to 1000 grit and polished to a very high gloss with Finesse It.  The pin is 4" from the cg. I put the pin above the fingers on my grip center line.  I put the cg 1" left of the grip center line. (This makes cg 6" from my axis). The statics ended up 5/8 oz negative and 1/4 oz thumb.  This ball goes very long down the lane and has a nice arc on the back end.  As long as I keep the speed up on the ball, the ball does not over react.  I must say for a urethane ball, this ball absolutely rolls great. I carry the 10 pin well with this ball and on light hits, I get good mixing action similar to a resin ball.  I think this ball is a real sleeper. I will punch another one to try on a heavier oil pattern.  This ball rolls as well as some of my resin equipment and hits just as hard as some of my resin equipment.  This is definitely one of the best urethane balls I have thrown in a while.  I do believe any serious league or tournament bowler should try this ball. You will not be disappointed.

Bought the Thunder Flash and was impressed, so when I saw people claiming the Thunder Flash Pro was even better I got excited. Had my Pro drilled label leverage with the pin at roughly 2 o clock from the label. My ball was about 2" pin out.

The first time I threw the Pro was with the surface at 400 wet grit and finessed (tm). The Pro let me move about 4 boards right in this configuration from where I was with the Thunder Flash (with factory surface drilled in identical fashion).

There was definitely less track flare, more tightly spaced and about an extra foot or two of length from the regular Thunder Flash, but the ball was still too much for the kind of drier conditions that I wanted to use it on even after 10 minutes in the Luster King machine.

I had the Pro sanded to 1000 wet grit and polished with Storm polish and after that the ball began to do more of what I wanted. The break on the back became sharper, but still very controllable and the Pro cleared the heads more readily.

With this surface I can cup the ball and use it on moderate to slightly heavy oil or keep the wrist straight and float it on a drier condition.

I am very impressed with how readily both of these balls coverstocks take a shine and the hit is the closest thing to reactive resin that I have ever seen in urethane. (If you like the Blue Hammer, you will absolutely love these balls)

If fresh walls have been killing you while the straighter players feast, I would definitely recommend one of these 2 balls. If you want to attack a drier shot the Thunder Flash Pro is probably better (once you get the surface tweaked). If you want to attack a medium to heavy shot, stay with the regular Thunder Flash -- it's pretty impressive out of box provided you have some head oil.

I haven't shot phone numbers with either of these balls yet, but I have been able to keep hitting the pocket and grinding out some very respectable scores on the type of shot that used to just kill me.