The only thing I would say about putting running spikes into the shoes is that there is a risk that the lack of a base plate around the stud will cause the whole thread to tear out when you persistently change direction (like if you are a bowler). Nike tried this in the very early days of their shoe development prior to entering the cricket market. The fast bowlers who were involved in the devlopment tore the soles to shreds and eventually Nike gave up on the idea. The base plate adds weight but it also adds resistance to the stress of changes in direction. While it is simplistic to say this, sprinters and track runners typically run in one direction and don't turn 180 degrees and sprint in the other direction. Anyway, just a thought for you to consider as you ponder weight vs cost of new shoes.