You might not like my answer, but here you go.
Do the seat lift mod. It's super easy. Super cheap. Should be less than 25-30aud. It helps a decent bit.
https://suzukisavage.com/cgi-bin/YaBB.pl?num=1109035237/5#google_vignetteConsider getting either a gel pad or an air cushion. I plan to buy a gel pad off Amazon for road tripping my S40. Expensive seats often use better foam with gel inserts inside their foam anyway. This method doesn't look the best, but it certainly is cheaper. Expensive seats add gel for comfort anyway. Something like this:
https://www.amazon.com.au/PhyiFlbey-Motorcycle-Absorbing-Absorption-Comfortab...Change your suspension. Your money will go a lot further with suspension. I did the Hagon shocks and had them shipped from UK to the usa. I could not find the thread about it sorry. I spent 280 dollars total to get them shipped here. They are adjustable as well. There's plenty of resources here regarding suspension. You will absolutely feel a difference. It will make WAY more of a difference than the seat.
And if you really wanna ball out, you could certainly modify to fit the seat of another bike. You could also find a specialist to customize your stock seat. There are a few places in the usa that will take a stock seat, rip out the foam, put some high end foam and gel, and upholster it back up for about half the price of a new aftermarket seat. Ask around. I have no idea if this is an option for you.