1) Using grammar when posting is nice. It is not hard to capitalize "I" and use proper sentance formatting. People tend to give alot more respect/credit/consideration to your post when you do this.

2) As for the feat itself:

What kind of action is the Tumble check? A Move action? Swift? Immediate? (should be Immediate)
Pre-reqs are a bit high for what this is. I'd drop the base Reflex save to 4 and the Tumble to 5 ranks. Thus, people who are not straight-classed rogue with maxed Tumble can get and benefit from this.
It should count against your movement, as this is possibly a very LARGE amount of movement in case of creatures with big reach.
If you fail the check you should still move, and provoke as you do so, as per the normal Tumble rules.


All-in-All a limited use but interesting feat.
Personally I'd give it some added benefit in addition, as the use is extremely limited. Maybe a free attack with your opponent denied his Dex? Would certinally be in-theme.