I have to agree with KeithH: get what you really want.
People told me not to get my 1st Supra. I did not listen to them and I was so glad to have it.
People told me not to get my bikes for so many reasons. I did not listen to them and I am I did not.
People told me not to get my MKIII. Again, I am so glad to do what I wanted instead.
One person's idea of heaven may be someone elses idea of hell, and vise versa.
To me, you don't seem so sure if you have to ask. I was always thrilled to get my machines -- I knew without a doubt that I wanted them. As far as cars go, I would not make a move unless I was 100% sure I wanted the 'car to be.' To me, it is not worth the transaction fees to get something I am not sure about.
I say keep the mkiii and buy the mkiv!
heh For me, one Supra is enough.