Yes, the main difference is the extra 0.5 and especially the turbo. The VF34 cost me £420 2nd-hand and was recommend by AndyF, along with the TD05 20g. I was lucky enough to get the turbo, as it came off of another driver's written-off car. When I had never seen the TD04, but when I looked at it on the garage floor I thought, "is THAT my turbo?". It was quite a bit smaller than the VF34 and limited power gains are available with it. Driving the car with the V34 even sounds different, you can hear it whoosh as it spools up and when I left of the gas I can even hear the standard DV blow off, so its a new experience. It will take a bit of getting used too as well.
I never thought that I'd ever mod my car at all, but I am SOOO glad I did. Can't wait till Saturday and KH to see what it can really do... standard brakes though, hmmmm that's going to be a prob!