Well Lag is not going to be a big deal on T28s, but if u want to improove the flow the Cheap/hard way go get ur self a port and polish kit and do that to your stock manifolds we found real good improovements, but definitly if u can afford tubulars plus u have a good machine shop to do them go fo it....(u can always use NOS and it'll spool up REAL quick) LOL!!