You're fine with a 4x AGP Ti4200. I'm sure!
I had the KT4V-L (well, I still have it but I just upgraded to an Abit board) and ran it for 8 months with a 4x AGP Ti4200 in it. It will run absolutely fine! Just make sure to manually set the AGP speed to 4x in the bios, and make sure it's set at 4x in the nVidia control panel that's part of the Detonator drivers.
I don't believe you have to update the bios to use over an 1800+. I was able to run a 2100+ when i first bought the board, without any bios updates. Of course I did update the bios when a newer one became available, and that's something that you'll most likely want to do no matter what motherboard you get. If you can stretch an extra $20 from your budget, I'd highly suggest getting an nForce2 mobo, like an Epox 8rda+ or even the MSI nForce2 board. Both should be available on the net for $90-100 USD. I loved my KT4V-L, but after just 2 days of using an nForce2 board, I'm highly impressed over the KT400 chipset.
Good luck!
