Dont be that much of a cheap bastard.

If you get the 370dx(with those sharktooth inlays)which is the best of what you listed there,you will run into a few things.

1.The trem is the edge pro II(or low TRS)... made with crap parts and just not as effective as the regular edge pro or Low pro.If you were to upgrade it would cost you at least 120$ if not 170$.

2.The woods the guitar is made from arnt all that great.Forget the mahogony body.You CANT feasibly upgrade a guitars wood.The finish is also most likley cheap and FAKE if it looks flamed or quilted(a photo top...although I dont think the 370dx has that).

3.Hardware,pickups and overall workmanship WILL be poor compared to any higher model.Uprading these will set you back even further.

By the time your finished,you will still have the same guitar,but with upgrades... it will still have close to the same value,and the orginal cut and construction of the guitar will still be there.

My advice would be to get a prestige model.Just overall better guitars.Go to guitartrader.com and take a look at the prstige models.Compare specs with the lower RG line.Youll see what I'm talking about.the RG1220 is around 450$ but its a large leap above the 320dx.Even the highest end regular RG model(the 570 I think)dosn't compare as well to the prestige models.The prestige RG's are still RG's,but to a higher standard.Its worth the little extra money.