What I can never understand is people buying a 8v then wanting to make it quicker, why not buy a quicker version in te 1st place. 
maybe found a mint 8v shell, or know and worked the 8v shell like I have....Out of boredom, maybe as something to do on the side.
1.8t conversion is expensive and there's more electronics involved. The 16v route is straight forward and easy to acquire.
TBH it's easier to buy a 16v but you've done a swap yeah?
So speaking from experience, you'd deffo do it again if you could go back in time, yeah?
So it's worth it. 
If I got the choice again of 1.8T or 16v, I'd probably go 1.8t route purely because in MY case, the 16v turned out to be a bit of a dog that needed some very expensive parts. However, if the 16v is acquired cheaply enough, I'd go for the 16v route again.