B&K upgrade?

I'm thinking of upgrading my current B&K ST-140 (105wpc) to a B&K EX-442 (200wpc). I'm driving a pair of Magneplanar IIBs. Will this be a good idea, or a waste of money. Please be kind I'm a newbie.
I sent in my 307 reciever for a 507 upgrade making it a 317. I thought the $465 was well spent. If i had replaced the 307, it would have cost three times as much. Also, the techs at B&K went through the unit and fixed a Toslink connection at no charge.
I did this upgraade several years ago. You get a more detailed sound with a 442. Bass is not muddy like with the 140. It is a worthwhile upgrade on a budget.

Enjoy the music.
If you plan on keeping the B&K long term that might be a worthwhile investment however, in my experience I had an ST-140 driving Vandersteen 2CE sigs. I sold the ST-140 for 225 and I went to a B&K Ref 4420 which had 225 per channel which I bought for $600. I sold it for a bit more then went to a McCormack DNA-1 for $800 which is 180 into 4 ohms but, drove the Vandy's easier, with better detail, stronger bass, etc... You can pick one up for about $800-900 and the deluxe model is a bit more. McCormack amps can be upgraded to what many consider world class.

Anyway, just another option....
I would consider borrowing a few other amps to demo with your speakers. I used a BK 202 to drive Maggie IIIa's for several years and had no idea what I was missing until I tried some amps with more juice. The first I tried was an adcom 5802, designed by N. Pass, and the improvment was like night and day.