The vest that Sgt. Greg PARKER (Enrico COLANTONI) uses appears similar to the "LAPD SWAT" vest seen here:
Link
The difference being that PARKER does not wear any of the external protective pads.
The remainder of the team generally appears to be wearing the BLACKHAWK! Omega Elite Tactical Vest seen here:
Link
All members appear to be wearing a non-specific black tactical thigh holster, so you could get away with using almost any of them. Though in other photos on the interwebs they also appear to be using the Safariland 6004 Tac thigh holster, a popular holster with law enforcement. They use (as witnessed in several episodes) the Glock 17/22 model, a larger sized pistol, so for authenticity sake your G27 may be a little small. But, that is assuming you want to ago 100% authentic.
The grey uniform is definitely a two-piecer, you could probably go with the 5.11 Tactical TDU Pant in #030 - HRT Grey. Assuming you plan on using the uniform often, I recommend the rip-stop model to prevent any accidental damage to it.
Patches.....I'm going to go on a limb and say you may need to custom make them. If you know someone good at replicating patches, acquire an old MTP (Metropolitan Toronto Police) shoulder patch and replace the wording with "METROPOLITAN POLICE" on the outside ring. The one you're looking for looks like
this. As for the actual "SRU" patch with what appears to be an unknown image with an "x" below it (someone feel free to correct me on the actual image since it appears I can't seem to find one with a big enough and clear enough shot) you'll probably have to get it custom made as well. There is a pretty clear image in the DVD book, I'll scan it and upload it tomorrow (4 Jan 10) when I get into work. Online, this is the best image I could find:
Link
On a side note, does anyone else find it funny that they use MP5's and yet their vests are designed to hold 30rd AR-style magazines?