I would really like to drive Ren 80 with two amps, but I am on a tight budget. So, yes, I know a pair of Pass Lab would be ideal, but that is way out of my budget. Currently I have a B&K 4420 (200 W @ 8 ohm; 350 W @ 4 ohm). Thinking about using it to drive the woofers and find another amp to drive the tweeters. Would a 100 W or even 70 W amp sufficient to drive the tweeters of a Ren 80? Any recommendations for a used non-expensive amp to be used with the existing B&K 4420 to do bi-amping? When I say non-expensive, ideally a few hundred dollars? Thank you very much.