Here is my race report of 2012
viewtopic.php?f=15&t=7771I tend to put in a lot of detail / waffle so may be of interest.
For a sub 5 on the Vit, based on your Sierakow result I would guess you need to be aiming for
Swim 32:00 - 33:00
T1 1:30 - 2:00
Bike 2h 30 - 2h 35
T2 1:00 - 1:30
Run 1h 50
I think you will pull in those extra minutes on the run as run course pretty decent compared to Sierakow, except a little climb and some grass.
Vit has 640m of ascent v Sierakow 760m so pretty well matched but do not underestimate the Ripples get them wrong and it hurts that's why you need to pile it on before you get to the railway bridge before Ripple 1, hammer it down as you crest to help you up Ripple 2. Ripple 3 can catch you out if you don't respect it and Steadman lane is a drag but ideal place to do your hydration replen. Suggest BTA bottle and replen bottle on downtube, Suck on BTA to Steadman lane, grab snack, dump contents of replen bottle into BTA, end lap 1 feed station dump replen bottle, quick dump of some of fresh replen bottle into BTA, stow replen bottle, lap2 Steadman lane remainderreplen bottle into BTA grab 2nd snack.
Hope that helps
So yes a sub 5h doable