FWIW I ran

S1X
1.8RR
S3 Heads
Gen V 2.8/2.9" pullies
EWP
Ported LIM
N* TB
4" intake
LQ4 Maf
Titanium retainer
130# springs

on SLP's. no flow issues at all. My biggest flow issue was that the last 4 feet of my exhaust was 2.5" stock with the stock Bonneville (high flow, low noise) muffer. And even that wasn't much of a restriction if you ask those that rode in the car.