Is this for 2-channel or HT? If it's for 2 channel music...
After having used monitors with a sub for many years, I just switched to floorstanders a month ago. Although my floorstander doesn't reach to the lower bowels the way my sub did, what it did uncover was an incredible amount of music and information in the bass I'd been missing all this time. However, the subs you're considering are very good, and may get you the bass quality I had missed.
If space permits, I'd suggest you consider combining your budget for monitor and sub or using 75% of it towards a really good full range speaker and spending the rest on the preamp/amp or on music/movies.
If your question is based on a home theater configuration, you can ignore my recommendation. I think a sub or subs would be essential for high impact movies.
After having used monitors with a sub for many years, I just switched to floorstanders a month ago. Although my floorstander doesn't reach to the lower bowels the way my sub did, what it did uncover was an incredible amount of music and information in the bass I'd been missing all this time. However, the subs you're considering are very good, and may get you the bass quality I had missed.
If space permits, I'd suggest you consider combining your budget for monitor and sub or using 75% of it towards a really good full range speaker and spending the rest on the preamp/amp or on music/movies.
If your question is based on a home theater configuration, you can ignore my recommendation. I think a sub or subs would be essential for high impact movies.