MainzMan:
I'd wait 5 levels and get the TM Speedblades. If you wait another 4 then you can save 400 credits and get the Rocketbladez which appear to be exactly the same.
After that the L85 Nike irons are pretty much a no brainer.
This assumes credits aren't an issue.
+1 regarding the recommendation to upgrade to the L75 TaylorMade Speedblade Iron Set. They are, or they have been to me, a really fine addition to my inventory. I was previously using L30,s TaylorMade R11,s and the performance improvement is spectacular.