The motor i have in my new bug is interesting
It is a 1916 built by Peter Shelley
http://www.cvwc.com.au/menu_page.htm
This motor is basically a 1600 with 94piston and cylinders and a slightly different cam. It still runs a stock exhaust and carb.
From all the dyno days i have been to a health 1600 will do 40 ponies at the wheels at best.
Mine put out 50. That is a decent 25% increase over stock and i reckon there is another 5 ponies if i just add a decent merged header. This takes it to an extra 33% over stock.
It is very noticeable.
When i bought the car it came with all the receipts and the motor was $2700.
My previous car had a 1776. Although that made 60 odd ponies and was definitely more powerful it was no where near as smooth and it also had webers.
I LOVE Webers but they do require more tweaking (cleaning jets, adjusting linkage) Not a lot - but more than the single.
Fuel economy is the same with all my motors. 8km/L in the city and 10 - 12ish on the free way in a heavy Super.
The 1916 also runs heaps cooler.
For a daily driver this 1916 is the best bang for buck i have driven