Would the extra travel cause any issues for this frame ?
Would the geometry be changed , ie longer fork make it sit higher
at the front ?
I don't think it's a problem. It would be about 1 degree slacker. 5" travel in the front is not too high. Have you try the lefty max? I had the 140 on my Prophet, I love it.
Yeah, about 1 degree slacker and obviously your bars will be about 1" higher.
Effects on handling - the bike fill feel like the front end wants to "flop" around at low speeds and steep climbs and steering will be slower in tight situations.
It will feel better at high speeds and when pointed downhill.
Potentially more stress on the head tube and I guess it could void your warranty.
Less isn't MOAR