DefTech makes excellent, fast subs and they are front firing. You might also look into Hsu and SVS, although some designs are downward firing. This Outlaw Audio LFM-1 (designed by HSU) received rave reviews from TAS and is moderatly priced. It too is downward firing sub tho. As with Shokhead, I'm a little confused why don't want a dwf sub, but I'm sure you have your reasons.

Woochifer has the Adire and loves it, IIRC. That could be the winner.