Start off with the lower setting and learn how to read the plugs and tune it. I ran 175 for years on a stock bottom end with no issues at all, tune up like anything is critical.
Do some small pulls turn the car off and read the plugs....only true way to know what is going on, if you let it idle it will change the reading on the plug. The bleuing on the ground strap will show you how your timing is doing, the porcelin will tell you how it is running rich/lean. I have a Moroso spark plug magnifier and it is worth every penny.
The NX stuff is very nice, be sure to blow out all the lines before installing, also never use TEFLON tape, always use liquid. I have 2 brand new 2-1/16" Autometer Phantom pressure gauges if your interested, white faced.