Looking for Tempo Shoe Recommendations

Hi all,

I've run casually for a bit but I'm starting to get more serious with it. I usually run 3 x 10km each week on pavement. The longest I see myself running is 16 km.

I currently have the Gel Nimbus 28. I like them but they do feel a little unresponsive when I push the pace. I'm looking for a shoe that I use on tempo runs. I want to stay with Asics. Any recommendations? I am thinking about getting the Megablasts.

Here are my times:

5k: 20:49

10k: 45:00

Physical Measurements: 29m, 5'4" [163 cm], 138 lbf [63 kg]