I had a Mustang. Loved the scale. Hated the bridge. Hated the bridge so much that I sold the guitar. I bought it the day of the price increase and got it for the old price. I sold it used for the old price and lost nothing on the transaction. Some day I'd like to get another one but a Warmoth knockoff made as a hardtail. But I doubt that will happen.
Actually would probably be cheaper to buy a Squier Duosonic an do some rewiring and repaint the instrument.
You can tension the springs somehow by the way they are positioned. I forget how it's done off the top of my head but google it.
I personally have no issues with those trems, I have a 1966 mustang and the trem stays in tune, love those guitars.