If the L24 is still ok and servicable, I would put it back together and run it like that until you know what you want to do. Like @Zed Head said, doing one mod without the other will not do much, but empty your wallet.
I'd drive it around for a while, enjot it, and think about what you want from the engine. Then gather all the parts for an engine project. You could use the L26 as a starting point.
I think the biggest buss for your money is a lightened flywheel. It doesn't add any horsepower, but it certainly gives a standard engine kick in the a$$ response. Very revvy and a little touches at the traffic lights, but managable once you get use to it.
My wife keeps stalling mine, but then she refuses to drive it because it's got no power steering, no power windows, no power mirrors, blue tooth or navigation, this list goes on.
Looks like you are having fun restoring it so far. It's your project, so you can do what you want when you. Just my 2 eurocents.