Like Jgrove998 said it all depends on your setup. If you plan on going higher than 20psi might as well get the 30psi gauge, there the same price.
SVT: Topmount GT3582R, SAE ? Whp ? Tq, Built motor, stock head, new #'s coming soon ;)
ZX3: RACE GAS 602whp 501tq Pump Gas SAE 454whp Garrett GT3582r, Topmount, built motor, Ported head, both Tuned by Fernando@RacingPartsSolution