I'm assuming you drive a mk5 GTI? There's plenty of options regarding upgraded engine mounts, Vibratechnics or Revo are some good options, check out the selection available here;
http://www.awesomegti.com/car/vw/golfmk5?subpart=MountsInitially, you'll be best investing in replacement OEM top left and right mounts and upgrade the dog bone and sub frame mounts. This should help you stiffen then engine up and stop it moving about but by replacing the main top left and right mounts with OEM you won't get harsh vibrations in the cabin as upgraded mounts will shake your teeth out for a while till the wear in!
For replacing the down pipe, you're probably best going for a stainless steel sports downpipe from the likes of Milltek or BCS. While those two companies are the most expensive systems, they're by far the best quality. You will need to get your R-Tech map tweaked accordingly but you'll unlock more power and economy by going down this route.
If you're replacing broken things, upgrade them to after market items which will last much longer than the car will!