For
Stock
Boost
Levels
up
to
15
psi:
Use
Colder
Range
Stock
Plug
PFR6B-11B,
Smooth
Daily
Driver
'7'
Heat
Range:
Stock
Turbos
(15+
PSI
level),
Sport
500s.
530s,
&
600s.
Great
for
street
use.
"8"
Heat
Range:
For
those
who
race
at
high
boost
levels
and
any
upgraded
turbochargers.
Good
for
nitrous
as
well.
Great
for
street
use.
"9"
Heat
Range:
Race
use
only!
Great
for
high
boost
and
nitrous
use.
Not
recommended
for
daily
driving.
Set
of
6
included
