I bought my H/C/I combo, now.......pushrods?

Pushrods are one of those parts you buy all of them new together. Also the easiest way to save time and money is to get a pushrod checker. It allows you to measure what length you will need with the components intact. Unless you have a completely stock car it's impossible to guesstimate what size you will need with an aftermarket setup and various wear tolerances.

As far as fuel injectors go it all comes down to how big in the future you want to go, if it were me 30's are in the range wear they support a n/a combo and can venture into the boosted territory in mild setups. The big thing to remember when you venture into fuel injectors is the tuning aspect of it. Your stock eec is based upon a stock injector size of 19lbs and a stock maf calibrated for the 19lbers. Throwing 30's on there will disrupt alot of eec varibles and will need to be addressed in some way (fmu, recalibration of maf, custom chip or personal programing tweecer/moates/etc.)