I put my 24 GX550 OT coilover onto the 250.
With the gx coilover on it is 21.875" Hub center to fender lip.
From what I can find stock height is 20.75" hub center to fender lip.
Increase height of 1.125
I bet the 25 springs will net a 2-2.5" height increase.
I would recommend the 24 springs...
For the rear spacers I recommend the following:
Brake lines (these are for a tundra which are already longer than the 200 series and then 2" longer)
https://toyteclifts.com/ss-tun7-extended-rear-brake-lines-for-07-tundra.html
Rear axle breather line
This fuel line works...
Since I have some stock 24 GC550 OT coilovers sitting on the shelf, I guess I could slap them on the 250 to see what height they put the 250 at.
Then it should be pretty easy to tell how much increased height the 25 GX550 OT springs would give a 250.
Cheaper option would be to make another part. you would have to drill an tap some holes in the main bumper part.
I can do these parts for around $100 for 2, if enough people want them. I would put 2 tapped holes in them to secure your mud flap.
I think, you're asking if I can extend it like this?
How much farther should I extend it?
From your pic, maybe extending to this surface looks about right.
When the engine is off, you should be able to move the fan, but there will be resistance. If it spins freely the clutch is shot.
Start watching from 3 minutes. @Timmy65 lists the diagnosis procedures