[L473ncy]

Depends on what brand of spring you get since the nomenclature might be the same but the actual outputs may be different, check the ASC spring chart and other websites as to what speed you'll get. M100 or M110 sounds like what you want though.

I believe you can use FTK's for different models however with the caveat that you may not get the right parts for your gun (eg. the kit is for a V3 gearbox however the cylinder might be for a longer or shorter gun that what you have).

I don't think gear ratios matter too much with a low FPS setup like what you have but I'd go with a set of high torque gears or standard gears.

Ehhh that's about right for length, although you'll probably need to change the cylinder (if you get an FTK just get a set that includes a cylinder for a longer barrel).