Mate. Go the TFS Track Heat heads. They should have the 7/16 studs and I've got the TFS 1.6 Rollers ready to go for $350 (cheap). Add the TFS middle range cam and you'll have a weapon combo.
Then do what I did. Sell the standard stuff to someone else and use the cash to justify how little you actually spent to upgrade.
BA'1.5' Pursuit 290
Lightning Strike / Reflective Orange Stripes
'General' Dog - AP's German Shepherd and Best Mate - 02Dec1998-15Dec2003.
'Pepper' Dog - General's and My Little German Shepherd Sweetie - 1996?-02Apr2006.
'Sako' Dog - My Beautiful and Pretty German Shepherd - 2001?-23Aug2006.