I have run socks ramtubes on 2 Escorts with twins for over 15 years and never set one alight with a backfire.... As I said - MAKE SURE YOU TUNE THE CARBS... And you can run a decent sized ram tube with socks that you CANNOT inside a K&N as you need some space (ideally the diameter of the ram tube) between the end of the ram tube and the end plate and between the end plate and the inner guard for the K&N.....
K&N flow very well for a filter and are a great filter, but for all round drivability you want to run as long a ram tube as you can. For max power a short ram tube will suffice, but the bigger the cam, the more likely the carb is to spit out a short tube.... (But one of my cars runs a 520X and does not spit out with the longer ram tubes!)
Sterling - Have a look at what 90% of rally cars running sidedrafts - see what they run... If you look at what the "competition cars" are running vs the "show / road" cars, you will find a similar answer...
On paper the K&Ns wins and looks much nicer (hence used on 90% of the shiny Escorts), but in the real world (where the cars performance is key and the paint not so shiney), socks do a better all round job (allowing the use of longer ram tubes as the biggest benefit) and hence a more ballanced real world performance.
Stering - What do YOU want?
Here endeth the lesson....