[azsarge]

200 will get you a good deal of upgrades.

Things I recommend:
-Systema BoreUp kit (includes new full cylinder, a silent piston head, a new cylinder head)
-Appropriate spring (PDI 170%, Systema M120, etc)
-Systema Air Seal Nozzle
-Guarder or Systema Steel Bushings
-Systema bearing spring guide
-Systema Torque-Up Helicals

You should be able to get all that stuff for under 200.  Add a tightbore for a couple more FPS and great groupings, and don't forget some new packs to push that beast.  If you have money left over, get some other parts like a tappet plate, piston just in case the stock ones strip.  

Since the M4 and Model 733 both use the version 2 gearbox, all parts are compatible.  

*I assume by "metal siding panel" (lol) you mean the gearbox.  Your stock box should be fine for awhile, but expect to replace it sooner or later.  A CA reinforced box is a perfect replacement for about 45 bucks.

[Sifu456]

Thanks that was a detalied and informative answer, I can order the parts over the net. B
Would the $200 include installed or just the parts?

Should I risk trying to install these parts myself? And whats is the list of tools needed for such a job?


Should I tape mark or place the screws and parts in marked cups or is it simpler then that???
 
What performance improvement would I see?

[azsarge]

Read Harleys write-up at http://www.airsoftarizona.com/reviews/tm_aeg_m4commando_reviewed_by_harley.htm for instructions.  Airsoftplayers.com also has some good intros to the world of mechboxes.  If you have a TM box, you will need a torx driver.  If you have a CA, a flat head and phillips head driver will do.  You shouldn't need any tools to get the AEG down to the mechbox, other than a screwdriver.  After that, the screws you see are the only things that require tools.  

I'd try it yourself.  If it works, it's a great feeling of satisfaction.  If not, take it to someone.  

The 200 covers parts only.  It should put you around 380-410 fps.  Guessing here, since every AEG is different.

[Sifu456]

Whats the best and safest upgrade for the M733?
Within reason I'm wanting to put another $200.00 into it, can I get a gear/spring/
metal/bushin and a metal siding panel, upgrade for about this price?

What do you guys think of stock piling parts for this rifle and how many parts/upgrades for M4* will fit the M733 internals?