Well, fair enough. But as I am sure you know, Einstein says nothing can travel faster than the speed of light.
Now obviously, like you said, the ETs found a loophole in General Relativity. More likely, or should I say more believeably to our current understanding of space and time, they use our theoretical wormholes to travel.
But, as for the possible crashing of alien vessels here on Earth and abroad, why not? Flight for a species without wings is always a risk.
That holds true for us and every other possible species across the cosmos. One malfunction and poof, we're going down.
On the topic of religion and the possible implications that alien visitation would have upon it are more likely to evaporate what little belief is left.
The "God" you know and love didnt create the world in 6 days, he didnt send his Son to to be crucified, his Son did not ressurect. Which basically covers all of Christianity as a fraud.
Same could be said for any and all religion.
The more likely scenario sees humanity as a whole embracing their visitors as something just short of Gods. With that in mind, is it any wonder why "they" havent made their presence known in no uncertain terms to the world?
As for ID and all that noise, it has nothing at all to do with God.
Finding life beyond earth whether its a bacteria on Saturn or a crash landing of a sentient species on Earth proves only one thing, that there isnt a 'design' to life at all.
No ryhme or reason or predictable pattern. It proves that life is, in fact, a miracle. An anomoly. In the most perfect conditions that we know of (Earth-like planets, to our limited knowledge), the only thing that could be said is that life "COULD" happen, not that it will.
Is that not miracle enough? Isnt that enough to make you believe that "God" is as removed and aloof as we all pretend He is? Think of God as a forest starter, not a harvester, and I think you'll find His motives a little less centric and little more broad.
Maybe, just maybe, Life is God. No creator, no man in the sky, just Life. The ties that bind us to one another and to all things. Maybe that idea is "God".