i was considering on changing the tortion bars but i was confused about the crossmember,now its clear ,will the bigger tortion bars fit the original lower tabs ?
I'n not getting what you mean by "tabs." If you mean the adjusters up front? Yes. If you mean the lower control arms? Yes. If you mean the balloon seals and c-clips? Well, it's always a good idea to replace seals and attaching hardware anytime you replace suspension parts.
I would recommend you take a look at your adjusters, though. These have a tendency to corrode after so many years (they're as old as your car, more than likely) and sometimes strip out where the bolt goes through the plate. Not a bad idea to hunt down new ones. Again it's a safety thing. Hate to see you get everything together and start adjusting the ride height just to have the bolt strip out.
Since you're going to have the suspension apart now's the time to start thinking rebuild on it if you haven't already. P-S-T is an advertiser here and sells good parts. The polygraphite master kit is the way to go for a good pavement pounder. Add in KYB shocks all the way around if money allows. Again, if you're looking for a good pavement pounder.
That being said what
are the plans for the car? Drag like moparal was talking about? Pavement pounder to take out on weekends or drive to work on good days in the summer? Canyon carver? Firm Feel has a list of torsion bars with sizes printed to help aid in your search for the right ones. You might want to give them a call with what you plan on doing with the car and they'll be able to help set you up with the size you'll want to run.
Good luck.