piller gauges

[2step]

Need info, please:
I want to add the gauges that the factory left off my PT. Idiot lights are ok for unconscious drivers, but not for an ex drag racer.
What kind of sender will I need for an oil pressure gauge, 1/8 in. pipe or metric? I've seen piller pods in black, taupe and gray - full piller and shortys - 2ga. and 3ga. Do any of these replace the stock piller trim or do they all just add on? How about gaps or sloppy fit at top, bottom or sides? Do they match the texture of the stock A-piller on the passenger side?
My application is for a '04 GT in Gray but I'll consider painting to match.
I've seen the comments by DART55 from last spring, but i need more info about the sender. Also, www.vinylguy.com has pix that are helpful.
Keep cruisein'---