Bilstein or Boge, even a US made gas shock...
...will no doubt make a real difference if your old shocks are worn out.
Unless you are towing something heavy the regular shocks s/b fine for another decade, or so...
Actually the US made shocks that are available, for example, the Monroe LE10134 @ $85 per rear set, are (limited) lifetime shocks @ half the price.
With a good installation & a 4-wheel alignment you should be in business
'91 420 SEL @ 199K, '92 SVX @ 181K, '93 SC400 @ 86K, '93 Kaw ZX-11 @ 30K, '87 F250 @ 181K , 2001 Valkyrie Interstate @ 6K, Y2K Honda NightHawk 250 with 1.5K, '88 420SEL I.@ 179K & the 2nd latest, an '88 420SEL II.@ 210K runnin' parts car, '85 F150 300/NP435