go for offset one in my opinion if You don't like big muffler sticking out.
If You like big box sticking out behind the car go for muffler without offset wth holes in center.
Don't You wanna use sme of the propper made mufflers? Good choice is a stainless steel one - wil last for ever
I have a VWSPEEDSHOP (whole system with 1 5/8" headre) and I'm really happy with it.
Fits perfect, sounds grate and the most important thing... it doesn't go louder afther 1000 miles as the cheep one's do. I drove few thousend km with that muffler and its just perfect (eaven in everyday use and in big tris like Poland to uk and back
)
cheers
Tom.