I didn't do the mod--the person I bought it from did. As to the SLI mode, ATI's Radeon 9800 Pro can be linked in up to a 256 GPU configuration, though God knows what 256 Radeon 9800 GPU's could do.
Lemme see...in terms of raw performance (assuming any degree of scalability) that should still be performing well in, oh, about ten years.

****, if 3dfx had produced an 8-way V5 (despite being immensely huge and probably over $1800 to purchase) it'd still offer competitive performance. Double V5 6K performance would be pretty fast.
(except of course for feature set)
*Edited* Profanity removed. KenKun/Moderator