i have a afp 20g, with a few other tweeks incl; gruppe s headers and up pipe, standard top mount.
made 405bhp on 10% meths and NF mix
Now on straight V-power and running about 380bhp
as far as spool, i make 1.5 bar of boost at 3400rpm
I ran a 18g before the 20g, the 20g has much more mid range punch / pulls all the way to you need to change gear,
always thought the 18g ran out of puff