POWer PC G4 350mhz upgrade ..suggestions

[radioteur]

Hi guys, thanks to every one that put effort and time on this project  giving the voice to every os 9 user.
A while ago with few bucks I bought an original power g4:
Power pc g4 350 mhz Altivec  L2 1 Mb
video card  slot agp 2x  (ati 128 pro 2x 16mb SDRAM)
3 pci slots  33 MHZ 64 bit
756 SDRAM DIMM
Hd 10 gb ATA 66 5400 rpm

I had lot of fun  working and playing around with this machine but now it’s time to upgrade some specs and do something serious.
 
Considering the logic board/Mobo I have got, according to you wich are the best options to buy and upgrade in terms of extra perfomance/costs? ( I mean spending few euros not a fortune and squeezing out the maxium juice from the machine working under os9)

I would like to increase the perfomance on daily use and make acid techno  using: some old sequencers,some old vst and having some fun playing few 2000/2003 3d games (quake 2 ,carmageddon 2 for example)

hoping not to be out of topic

Thanks and best regards

[radioteur]

Any suggestions guys?
Please !