Old Library

The install for the Mk3 kit is VERY simple.  It's even easier than the old
Z-kit.  You don't need to tap the oil pan.  You can easily do this yourself.
If it wasn't so easy, I'd be going turbo ;)

The Mk4 kit is no comparison - it's far more complicated with pipes running
back and forth across the engine, intake on opposite side as charger, and
relocation of this'n'that.

There is no requirement to tap the pan for the MK3?!  Where does it get
oil feed/return from?

Answer: http://www.vf-engineering.com/faqmk3vr6sc.htm

"...kit is supplied with a T-piece fitting to use on the oil pressure
switch. You remove the switch from the oil filter housing and screw it and
the oil line into the T and then the T into the oil filter housing."

Stef,
But a bit farther down it says:
"Can I purchase a tapped oil-pan (sump) from VF-Engineering?
No. The oil return line is connected to the oil pan with a race industry quality hose and fitting.
The pan does not need to be removed for the fitting to be attached. A special punch tool is
provided in the kit to pierce the oil pan and a special tap for the pan to be threaded is also
included. A full explanation is provided in our instructions which details how to avoid metal
shards entering into the pan. "
So, I think you do have to tap into it for the return line.
Later,

Yeah, I have the MK4 kit.  For the feed, on the MK4, there is an extra
plug in the filter housing next to the pressure sensor that you remove,
and screw in the fitting for the feed line in place of.

For the return, they did include this special "broach cutter" tool which
installs in a drill, and you cut the hole as it pulls the filings out.  I
wasn't too comfortable with the possibility of filings in the pan, so I
cut the hole, let the oil drain out, then removed the pan.  I found quite
a bit of filings in the bottom of the pan, so I scrubbed it clean with
degreaser and reinstalled it.  Who knows, maybe I did something wrong when
cutting the hole, but I sure felt better about spending the extra hour or
so and cleaning up.

-Erik
'00 GTI GLX with tapped pan but no metal filings in it