I think I am going to purchase this pistol tomorrow.

http://www.fieldandstreamshop.com/p/browning-buck-mark-practical-urx-pistol/15brwaprctclrxgryhng

Are the finger grooves on the grip removable and replaceable with wood grips?

Which companies make aftermarket barrels that are threaded for a suppressor?

Great pistol! I bought one 8 weeks ago and have got 1,100 rounds thru it with only 1 FTE! You should check out "Sportsman's Guide for pricing. I got mine for $310. Best place for aftermarket stuff I've found is Midwest.
http://www.midwestgunworks.com/mm5/merchant.mvc?Screen=CTGY&Store_Code=mgwi&Category_Code=A-02-G-24&view_perpage=all

Be careful on grip selection, the frame for the URX is different and thus, grips are too. Browning makes wooden grips for it however.
Love this gun.

Ok which one is it? The link takes me to the URX while the title of the thread is UFX.

Here's my .02

I bought the UFX because I don't like the finger grooves. The URX as stated will need a certain style of grips to fit correctly. Don't think you'll have any issue with either just what style grip you prefer. My UFX I bought about a month ago. I've put 300 through it with no issues. I also put on the Dawson front sight and it shows up really well.

Good luck.

Didn't see mention of the suppressor barrel. Basically the go to here is with Tac Sol. They make a few different lengths as well as colors and profiles of barrel.