Like Builder said porting will give you the best gains for your buck. Adjustable timing plate will also give you a noticeable gain. A coolhead will allow you to use different domes. When increasing compression with domes you need to see what your compression is and check squish band. How much comp and squish will determine what octane fuel you will need to run. I'm not sure what break the bank is either, but when you start modding, its going to cost your ass. If you want to mod engine AND look good, its going to cost your ass twice as much. Have fun with it.