I have some flat , unmarked brand new rota centrecaps for the slipstreams. Check that the bolt for the hub doesnt stand further out than the cap would sit.. IE my rota caps fitted the wheels perfect, but the bolts for the hubs protruded from the wheel slightly, so i had to order some different caps that look like wheel nuts, so the axle bolt sits inside the cap if that makes sense I payed £5 each cap.. if youre bolts dont protrude further than the cap would sit, you can have mine for a fiver for all 4. Plus say about £2 for postage cost. Also check the rarerims website, thats where i originally ordered my rotas and caps from. Cant remember the website, just do a google for RareRims..