looking to either upgrade my exsisting amiga 500 or buy a new one outright if its modded nicely

for an expansion i mean any of those acceleratiors that fit onto the side of the amiga 500 that either give one a faster cpu, more fast ram or a hard drive. i'll also consider any kickstart rom switcher and things like that.

if anyone is selling an already modded A500 (KS switcher installed, harddrive, ect.) i would also consider buying it since it would save me the trouble of modding mine.