Not really since no other faith has a similar conception of salvation.
What do you mean by similar?
The concept seem pretty identical in Islam, for instance. Islam is the only path to/of salvation etc.
In any case, your point is irrelevant since it doesn't actually dismiss the charge of spiritual imperialism. In fact, if anything, claiming that Christianity is unique (i.e. "no other faith has a similar conception of salvation") serves only to strengthen it.