The way I look at it I do not think it is logical that God would have an obscure interpretation of salvation verses that prevents a percentage of seekers from becoming born again who desire that.
So no I don't think any ones belief regarding the Trinity affects salvation.
I do think Wierwilles Trinity explanation and book served to effectively erect a barrier between followers of TWI and all other denominations and community churches that has never been effectively broken down.
Twits are seperate and do not collaborate with other Christians at all. This is isolationist and contributes towards the climate of small groups of dictators running everything, the lack of voting privileges in the leadership body, and the general cult like feel of the group.
I feel that they live in doctrinal and practical error and are living examples of the eye saying to the hand “I have no need of you” as found in Corinthians the books they purport to be expert in and teaching the world about their take on it.