It would not work.

Not only is the emitter much larger than the stock emitter of the Wowtac A1(XHP 70.2 is much bigger than an XP G2), but the XHP 70.2 is a 6V LED, while the XP G2 is a 3V LED. You would need a new driver.

The only mod you could be able to do is put in a Nichia 219C, or an XPL HI for a bit more lumens and better color reproduction.