^I've done that too. It's a deal thing I have worked out. The car should run fine on 89 as long as I'm not romping it. my 335i does and it's TT. I need to at least make sure the knock sensor is good and the wiring is not shot.
DD: 2003 530i 5spd manual sport package. Conti DWS's, Llumar ATR, White LED lighting. TLC on-going.
Garage queen: '07 335i Sedan, base pkg, 6spd Manual, Procede 3 V5 w/NLS, staggered 18" 313's w/Conti DWS's, OS Giken TCD LSD, VAC Street Diff Cover, Akebono Euro Pads, CDV Removed, Black BMW Grilles, Interior & Exterior white LED lighting, LUX Angel Eyes, Debadged, Llumar ATR Tint.