Yes it is a good idea. The car will fly. But fully legal and safe and on the road is another matter.
No-one will be able to tell you how much it will cost exactly. First work out exactly what you want to do, search here, talk to mechanics, ring importers, read mags and get a good idea.
VERY rough guide - half-cut $2200
- fuel pumps, filters and lines $350
- Associated rooting around with hoses and stuff $500
- Plus engine mounts/crossmember mods
- Plus diff swap
- Plus big brakes
- etc etc etc
And that is assuming you do all the work yourself.
Get on the phone to your local raods authority and check the legality (may also pay to check insurance companies if you're that way inclined).