your opinion on subwoofers in two channel

If you are using monitors as speakers, adding a sub is a must in my opinion. You would get a bigger soundstage and more weight and body with instruments and voices. A sub adds the bottom frequency which in turn helps your middle and upper frequency sound more natural.
I added a sub when I had JM Lab Mini Utopia and could never turn back without a sub. Have fun.
Nickk

Depends on your two channel audio objectives, for each objective my suggestions are;

Balance of esthetics, quailty & function: get small moderately priced speakers (6" woofers or less, 6 db at 60 to 100 Hz) and a reasonably priced mid-size sub (8" to 10" woofer to cover 30 to 100 Hz). Great sound and looks good.

Pure high end audio: spend your money to upgrade to large expensive accurate LF range speakers (12 or 15" woofers, 6 db generally between 30 and 50 Hz) before ever considering a sub to complement the extreme low end (12 to 15" woofer at least to cover 20 to 50 Hz). Incrementally better sound than above with the drawback of big imposing boxes and significantly higher cost.

interesting thoughts and knowledge thanks i understand what both of you are saying...thanks

I think good subs that can be tweaked in to mate with your room & system do make sense and can add to the enjoyment in a meaningful way. Less adjustable subs or trying to do to much from a single sub can be more of a distraction than a benefit. And it depends on your taste in music. If there is little to be heard then a sub adds little (duhh, ok so that ain't such an epiphany).
To answer your question directly, if I had to choose between better sound overall or adding a sub, I'd take the former, but if I could afford the additional extravagence of one or two good subs I'd go for it. IMHO, YMMV, DEYS.