MAMEWorld Forums - Hardware - Amp for new MAME project, and ? about frontends

So I just purchased an Xtension Classic Arcade Cocktail Pro cabinet from recroommasters.com for my boy. I plan on picking up a 23" monitor and a refurb PC from newegg for it, but now I'm in the need of speakers and an amp. The speakers aren't much of a problem, by the looks of the images of it, I'll be able to screw in a couple of 5" speakers on either side. The trouble is finding an amp to run from the PC to power the speakers. I know I came across a PCB on one of the websites I researched that showed a cheap amp I could buy for it to power the speakers and I can't, for the life of me, remember which site I saw it on. Any help would be appreciated.

Also, I'm undecided about which frontend to use. I haven't built an arcade cabinet in years.. last one was like 10 years ago when I converted an old players-choice10 cabinet to a mame cabinet. Back then, the speaker issue was resolved by just mounting the speakers on top, and if I remember correctly, I just used the ArcadeOS interface with I believe windows 98.

I'm still in the planning phase with the Xtension Classic Arcade Cocktail Pro, since I just ordered it. I haven't ordered anything else, or committed to any other purchases until I have a more clear plan for the interface.

Should I maybe STILL go with Windows 98?? Don't really see any advantages to using XP or Windows 7 since I'm clearly gonna shell the OS for the frontend. I'm considering blowing the dust off the old windows 98 disc, because, for me anyway, it's easily the most fastest & hackable OS for an arcade machine... thoughts?? Suggestions??