i would suggest putting your money into the mechanics first. you will be much happier and have more fun with a good handling and more powerful car and safer with more modern upgrades (rear disc brakes, etc). don't make it all show and no go.
that say, do you have a super or standard? the dash pad is easy to install in a standard and relatively easy in a super. just install new carpet. the acoustics are better, it dampens road noise, and is easier to maintain (and cheaper too). easily a do-it-yourself job. there are an abundant amount of posts on seat options. you will find just about everything being done. you just have to fabricate the seat mounts. Porsche seats tend to be the favorite do to comfort and looks. if you don't plan on having more than 2 in the car, remove the back seat. saves weight and solves that matching problem.
