You can expect an increase of 3 to 4PSI (peak boost) but the real improvement is in the mid-range

upgraded camber arm and reinforced knuckle

Type: JRWA2

Brown/Black 3psi Inner Spring

Recommended for: Motorsport ApplicationsThese kits are available with sprung ceramic friction discs and are designed for motorsport applications where higher heat and torque capacity is required

Vesser VSR4 20x9 ET20-51 5H BLANK Custom Finish Ceramic coating You can expect an increasePCD: 5x108, 5x110, 5x112, 5x114. 3, 5x115, 5x118, 5x120, 5x120. 6, 5x127, 5x130 ET: 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51