Since I cant afford a complete new m4 type weapon I was thinking of picking up a pre ban Bushy m4 type upper and puttin it on my Colt SP1 lower. Will they fit ? Should I just go with Colt? I thought Colt prices might be higher? Any ideas appreciated. Thx and remember 9-11!

Figure out how much you want to pay, then start figuring out what options you want.  For some people, the Colt is the greatest thing since sliced bread.  Others want an all Bushy or other matching AR.  I just want a weapon that works all the time, names mean little to me and yes one of my ARs is a Colt.  

Do you need a chrome barrel?  If you do then the Bushy or Colt are your options, with RRA maybe getting into the game soon (I think RRA is on and off with M4 chrome barrels right now).  Any of them will shoot fine.

If you don't need or want to pay the extra for a chrome barrel, there are plenty of other makers out there. Take a look at some of the kit guns if you need the adjustable stock and upper, or just look at uppers if you don't need the stock. JT distributing has a M4 upper for $330.

A last thing to think about is getting a stainless steel M4 barrel from Olympic Arms.  If you already have a CAR style rifle, they can drop a new SS barrel in it for you.  Of course they also have the full uppers, and there are certainly other places that do new barrels as well.  The Olympic M4 barrel in Stainless Steel is around $185.

If nothing else, I hope I gave you a few ideas that maybe you hadn't thought of.  Good luck.