I'm not quite sure how to do that haha. I'm a bit new to this whole guide thing. Any suggestions?

As far as the attack speed marks go I'm still trying to find time to test them out in a few normals games. I can see how they would help your first few clears and your DPS during ganks before people start buying armor though. After your first clear you really don't have any problem burning the jungle down (just a Spirit Stone does wonders for Vi) even without attack speed runes, the base damage on all your skills is actually quite high for the cool downs.

The main reason that I prefer to take Vault Breaker at level 2 instead of Relentless Force is because it massively expands your level 2 play options. Taking Relentless Force at level 2 doesn't just commit you to farming the jungle, it also greatly reduces your early game damage and makes you vulnerable to level 2 counterjungling (something which you start to see a lot when you play solo queue with plats). Vault Breaker deals between ~60-120 damage to everything your way with AD marks and quints, lets you cross walls without burning Flash, gives you cc to contest buffs better or gank earlier, while Relentless Force only gives you an auto attack reset with ~80 damage to everything behind your auto attack target. Not only does Vault Breaker make your early jungle safer, but it's cooldown is only 4 seconds longer than Relentless Force's cooldown. Taking Relentless Force at level 2 just isn't as good. One last thing about your level 2 skilling options. You should pretty much always be getting the full channel on your Vault Breaker on your first few clears because you're using it to get to camps faster. You enter camps using Vault Breaker and you move to the next camps with Vault Breaker, Relentless Force just can't give that to you.

With the 3.15 patch going Spirit of the Elder Lizard and The Brutalizer just isn't a good option anymore. Vi benefits more from CDR and HP (as I stated in further down in my guide since it seems you just read the cheat sheet) the later the game progresses because it keeps her casting spells longer in team fights. To add to that, Vi actually has to get a defensive item in addition to those items if she wants to force an early dragon ( Spirit of the Ancient Golem lets you take dragon easily at level 4 with bot lane's help). Not to mention that you really can't afford to have only 3 real defensive items mid to late game, you'll just get blown up hard.

Now for Sunfire Aegis versus, say, any other defensive item. Sunfire Aegis is an item that you mainly see on top laners for a reason, it is primarily a split pushing item. If Vi is off on her own split pushing her team is going to lose fights, and if you aren't split pushing with Sunfire Aegis you aren't utilizing the item well. Randuin's Omen gives you much better stats and utility for Vi than Sunfire Aegis does for only 350g more. Locket of the Iron Solari gives you good all around defensive stats and great team snowballing potential (you really can't over look the legion aura and active shield) for 100g less than Sunfire Aegis. Adding to that, Sunfire Aegis just can't hold a candle to any other Giant's Belt item after 25-30 minutes. The stats it gives you are pretty mediocre, the passive is negligible late game when people have MR (MOSTLY FROM THE ENEMY JUNGLE/SUPPORT'S LOCKET) and you would actually have to sell it for something that actually has an impact on the game. Even Warmog's Armor is a better choice on Vi.

And masteries, meh, that's more a matter of personal preference and play style. Taking Dangerous Game and Second Wind (when you have a Spirit Visage in tow) give you +6.5% of your missing HP back when you kill an enemy champion, which is good since you tower dive a ton as Vi. You can go for something more early game focused (as most masteries really are) but I think it's one of the best late game options when combined with your item pathing and your Blast Shield passive.