Sam,
It boils downs to how much play money you have or if you don't care do as you intend. But all the mods you speak of will get your 3.5 to a 4.1 at twice the cost. And it will still have the 3.5 stigma. You can't mod it and then expect to sell it at more than what a v5 would sell new. This is what most newcomers need to come to terms with, there will always be a fix, an update worse than windows, ios or android.
Ultimately, it is what you want to do. As bmw said, just giving you advice but it is up to you. I have a v3 and it's ok as I don't think mine was particularly bad. The tells we all know are there. But because I don't care about them as it is not a rolex, it's all good.
When they get to version 10 and it is 99.9% then I'll upgrade and use the v3 as a daily beater.