Meh, PHP ain't a problem for me, I should have phrased my question better - is it possible to create a child theme and make these kind of edits?
I do not want to start creating custom modules and then have it overwritten when a new update is published.
(I currently use myBB and phpBB so I might be stuck in the mindset of how they do things and this might come off as a stupid question from your perspective as a invision user).
PS: Where is your forum hosted, I have used a few invision forums and they all feel dog slow to me, but I am not sure if it is because I sit in Cape Town and your forum and the invision demo forum sits in the other side of the world. To clarify, is sluggishness a known invision thing or is it just due to me sitting 400ms away and if I do a self-hosted solution this side my users should not experience it?