At the Miami Open I picked up several 95in headsize racquets to compare i.e., the Tec 320, Tec 325, BLX 6.1 95 (18x20) and the Yonex 95d.
Regarding your question comparing the BLX 6.1 95 (18x20) and the Tec 320: IMO... Power: The BLX has more plow or projection of force into the court, Spin: The Tec 320 has a little more spin, Feel: The Tec 320 allows you to feel more connected to the impact of the ball (more feel) but the BLX has a more buttery feel and more consistent string bed, Sweet spot: The BLX may offer a slightly bigger sweet spot but Tec holds its own in this department.
In general, I think the Tec 320 has a better feel for drop shot etc., it swings easier and faster... and it also is the best looking racquet than the BLX.
The main negative with the Tec 320 (and this is very very minor) is that the racquet has a noticeable drop off of power at the top of the string bed (which mostly affected the extended ground strokes not the serves).
The main negative with the BLX 95 was that it had slightly thick feeling (in the throat) when executing fast reaction shots (I tend to prefer a slightly more polarized racquet in general).
For me, I have to say that at this point in the comparison that the BLX 6.1 95 (18x20) is a better fit for my game (4.5) as i am better able to handle a heavy hitter, or a hard server, and in a fast moving game situation the BLX just seems to be more effective... That being said the Tec 320 is a great stick.