TC engines can be made to rev albeit with lower valve guide life. You can get forged cranks, heck, even cranks from billet. For the crossflow, not so much. Cam wear increases dramatically when you get above 7k. Cranks also have issues at revs.
Crossflows do, however, breath very well. Maximizing valve size, flowing the ports carefully give good results. The other thing easily (somewhat) done is increasing displacement. A reliable 1800 is no problem. I’ve seen 1950cc as well but no idea how reliable.
All this is a long way of saying that lightening the valve train isn’t necessarily the best place to open up the wallet. You can spend a LOT of money to get to 160hp (or more) and the soccer mom’s van will still smoke you at the line.
Finally, if you want more power, there are cheaper engines to build on that will make SERIOUS power.
