Any excellent quality boost gauge will work well. Accuracy is the important feature to think about. Autometer gauges are a great value. Asia gauges, A'PEXi, GReddy, HKS, etc., read more features, but at a significantly higher bargain.
Viii. If you learn any grinding sound or feeling if you shift into a new gear, have transmission check. Also if you notice anything besides a smooth transition between gears, then you can certainly might need transmission repair or alternate.